Internet DRAFT - draft-ietf-lamps-rfc4210bis
draft-ietf-lamps-rfc4210bis
LAMPS Working Group H. Brockhaus
Internet-Draft D. von Oheimb
Obsoletes: 4210 9480 (if approved) Siemens
Updates: 5912 (if approved) M. Ounsworth
Intended status: Standards Track J. Gray
Expires: 2 September 2024 Entrust
1 March 2024
Internet X.509 Public Key Infrastructure -- Certificate Management
Protocol (CMP)
draft-ietf-lamps-rfc4210bis-08
Abstract
This document describes the Internet X.509 Public Key Infrastructure
(PKI) Certificate Management Protocol (CMP). Protocol messages are
defined for X.509v3 certificate creation and management. CMP
provides interactions between client systems and PKI components such
as a Registration Authority (RA) and a Certification Authority (CA).
This document obsoletes RFC 4210 by including the updates specified
by CMP Updates RFC 9480 Section 2 and Appendix A.2 maintaining
backward compatibility with CMP version 2 wherever possible and
obsoletes both documents. Updates to CMP version 2 are: improving
crypto agility, extending the polling mechanism, adding new general
message types, and adding extended key usages to identify special CMP
server authorizations. Introducing CMP version 3 to be used only for
changes to the ASN.1 syntax, which are: support of EnvelopedData
instead of EncryptedValue and hashAlg for indicating a hash
AlgorithmIdentifier in certConf messages.
In addition to the changes specified in CMP Updates RFC 9480 this
document adds support for management of KEM certificates.
Appendix F of this document updates the 2002 ASN.1 module in RFC 5912
Section 9.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 2 September 2024.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1. Changes Since RFC 2510 . . . . . . . . . . . . . . . . . 6
1.2. Changes Since RFC 4210 . . . . . . . . . . . . . . . . . 7
1.3. Changes Made by This Document . . . . . . . . . . . . . . 8
2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 9
3. PKI Management Overview . . . . . . . . . . . . . . . . . . . 9
3.1. PKI Management Model . . . . . . . . . . . . . . . . . . 9
3.1.1. Definitions of PKI Entities . . . . . . . . . . . . . 10
3.1.1.1. Subjects and End Entities . . . . . . . . . . . . 10
3.1.1.2. Certification Authority . . . . . . . . . . . . . 11
3.1.1.3. Registration Authority . . . . . . . . . . . . . 11
3.1.1.4. Key Generation Authority . . . . . . . . . . . . 12
3.1.2. PKI Management Requirements . . . . . . . . . . . . . 12
3.1.3. PKI Management Operations . . . . . . . . . . . . . . 14
4. Assumptions and Restrictions . . . . . . . . . . . . . . . . 18
4.1. End Entity Initialization . . . . . . . . . . . . . . . . 18
4.2. Initial Registration/Certification . . . . . . . . . . . 18
4.2.1. Criteria Used . . . . . . . . . . . . . . . . . . . . 19
4.2.1.1. Initiation of Registration/Certification . . . . 19
4.2.1.2. End Entity Message Origin Authentication . . . . 19
4.2.1.3. Location of Key Generation . . . . . . . . . . . 20
4.2.1.4. Confirmation of Successful Certification . . . . 20
4.2.2. Mandatory Schemes . . . . . . . . . . . . . . . . . . 20
4.2.2.1. Centralized Scheme . . . . . . . . . . . . . . . 20
4.2.2.2. Basic Authenticated Scheme . . . . . . . . . . . 21
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4.3. Proof-of-Possession (POP) of Private Key . . . . . . . . 22
4.3.1. Signature Keys . . . . . . . . . . . . . . . . . . . 23
4.3.2. Encryption Keys . . . . . . . . . . . . . . . . . . . 23
4.3.3. Key Agreement Keys . . . . . . . . . . . . . . . . . 23
4.3.4. Key Encapsulation Mechanism Keys . . . . . . . . . . 23
4.4. Root CA Key Update . . . . . . . . . . . . . . . . . . . 24
4.4.1. CA Operator Actions . . . . . . . . . . . . . . . . . 25
4.4.2. Verifying Certificates . . . . . . . . . . . . . . . 26
4.4.2.1. Verification in Cases 1, 4, 5, and 8 . . . . . . 27
4.4.2.2. Verification in Case 2 . . . . . . . . . . . . . 28
4.4.2.3. Verification in Case 3 . . . . . . . . . . . . . 28
4.4.2.4. Failure of Verification in Case 6 . . . . . . . . 29
4.4.2.5. Failure of Verification in Case 7 . . . . . . . . 29
4.4.3. Revocation - Change of CA Key . . . . . . . . . . . . 29
4.5. Extended Key Usage for PKI Entities . . . . . . . . . . . 29
5. Data Structures . . . . . . . . . . . . . . . . . . . . . . . 30
5.1. Overall PKI Message . . . . . . . . . . . . . . . . . . . 30
5.1.1. PKI Message Header . . . . . . . . . . . . . . . . . 31
5.1.1.1. ImplicitConfirm . . . . . . . . . . . . . . . . . 35
5.1.1.2. ConfirmWaitTime . . . . . . . . . . . . . . . . . 35
5.1.1.3. OrigPKIMessage . . . . . . . . . . . . . . . . . 35
5.1.1.4. CertProfile . . . . . . . . . . . . . . . . . . . 35
5.1.1.5. KemCiphertextInfo . . . . . . . . . . . . . . . . 36
5.1.2. PKI Message Body . . . . . . . . . . . . . . . . . . 36
5.1.3. PKI Message Protection . . . . . . . . . . . . . . . 37
5.1.3.1. Shared Secret Information . . . . . . . . . . . . 38
5.1.3.2. DH Key Pairs . . . . . . . . . . . . . . . . . . 39
5.1.3.3. Signature . . . . . . . . . . . . . . . . . . . . 40
5.1.3.4. Key Encapsulation . . . . . . . . . . . . . . . . 40
5.1.3.5. Multiple Protection . . . . . . . . . . . . . . . 45
5.2. Common Data Structures . . . . . . . . . . . . . . . . . 46
5.2.1. Requested Certificate Contents . . . . . . . . . . . 46
5.2.2. Encrypted Values . . . . . . . . . . . . . . . . . . 47
5.2.3. Status codes and Failure Information for PKI
Messages . . . . . . . . . . . . . . . . . . . . . . 49
5.2.4. Certificate Identification . . . . . . . . . . . . . 50
5.2.5. Out-of-band root CA Public Key . . . . . . . . . . . 51
5.2.6. Archive Options . . . . . . . . . . . . . . . . . . . 51
5.2.7. Publication Information . . . . . . . . . . . . . . . 52
5.2.8. Proof-of-Possession Structures . . . . . . . . . . . 52
5.2.8.1. raVerified . . . . . . . . . . . . . . . . . . . 52
5.2.8.2. POPOSigningKey Structure . . . . . . . . . . . . 52
5.2.8.3. POPOPrivKey Structure . . . . . . . . . . . . . . 53
5.2.8.4. Summary of PoP Options . . . . . . . . . . . . . 57
5.2.9. GeneralizedTime . . . . . . . . . . . . . . . . . . . 58
5.3. Operation-Specific Data Structures . . . . . . . . . . . 58
5.3.1. Initialization Request . . . . . . . . . . . . . . . 59
5.3.2. Initialization Response . . . . . . . . . . . . . . . 59
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5.3.3. Certification Request . . . . . . . . . . . . . . . . 59
5.3.4. Certification Response . . . . . . . . . . . . . . . 60
5.3.5. Key Update Request Content . . . . . . . . . . . . . 61
5.3.6. Key Update Response Content . . . . . . . . . . . . . 61
5.3.7. Key Recovery Request Content . . . . . . . . . . . . 61
5.3.8. Key Recovery Response Content . . . . . . . . . . . . 62
5.3.9. Revocation Request Content . . . . . . . . . . . . . 62
5.3.10. Revocation Response Content . . . . . . . . . . . . . 62
5.3.11. Cross Certification Request Content . . . . . . . . . 63
5.3.12. Cross Certification Response Content . . . . . . . . 63
5.3.13. CA Key Update Announcement Content . . . . . . . . . 63
5.3.14. Certificate Announcement . . . . . . . . . . . . . . 63
5.3.15. Revocation Announcement . . . . . . . . . . . . . . . 63
5.3.16. CRL Announcement . . . . . . . . . . . . . . . . . . 64
5.3.17. PKI Confirmation Content . . . . . . . . . . . . . . 64
5.3.18. Certificate Confirmation Content . . . . . . . . . . 64
5.3.19. PKI General Message Content . . . . . . . . . . . . . 65
5.3.19.1. CA Protocol Encryption Certificate . . . . . . . 65
5.3.19.2. Signing Key Pair Types . . . . . . . . . . . . . 66
5.3.19.3. Encryption/Key Agreement Key Pair Types . . . . 66
5.3.19.4. Preferred Symmetric Algorithm . . . . . . . . . 66
5.3.19.5. Updated CA Key Pair . . . . . . . . . . . . . . 67
5.3.19.6. CRL . . . . . . . . . . . . . . . . . . . . . . 67
5.3.19.7. Unsupported Object Identifiers . . . . . . . . . 67
5.3.19.8. Key Pair Parameters . . . . . . . . . . . . . . 67
5.3.19.9. Revocation Passphrase . . . . . . . . . . . . . 67
5.3.19.10. ImplicitConfirm . . . . . . . . . . . . . . . . 68
5.3.19.11. ConfirmWaitTime . . . . . . . . . . . . . . . . 68
5.3.19.12. Original PKIMessage . . . . . . . . . . . . . . 68
5.3.19.13. Supported Language Tags . . . . . . . . . . . . 68
5.3.19.14. CA Certificates . . . . . . . . . . . . . . . . 68
5.3.19.15. Root CA Update . . . . . . . . . . . . . . . . . 68
5.3.19.16. Certificate Request Template . . . . . . . . . . 69
5.3.19.17. CRL Update Retrieval . . . . . . . . . . . . . . 70
5.3.19.18. KEM Ciphertext . . . . . . . . . . . . . . . . . 71
5.3.20. PKI General Response Content . . . . . . . . . . . . 71
5.3.21. Error Message Content . . . . . . . . . . . . . . . . 71
5.3.22. Polling Request and Response . . . . . . . . . . . . 72
6. Mandatory PKI Management Functions . . . . . . . . . . . . . 77
6.1. Root CA Initialization . . . . . . . . . . . . . . . . . 77
6.2. Root CA Key Update . . . . . . . . . . . . . . . . . . . 78
6.3. Subordinate CA Initialization . . . . . . . . . . . . . . 78
6.4. CRL production . . . . . . . . . . . . . . . . . . . . . 78
6.5. PKI Information Request . . . . . . . . . . . . . . . . . 78
6.6. Cross Certification . . . . . . . . . . . . . . . . . . . 79
6.6.1. One-Way Request-Response Scheme: . . . . . . . . . . 79
6.7. End Entity Initialization . . . . . . . . . . . . . . . . 81
6.7.1. Acquisition of PKI Information . . . . . . . . . . . 81
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6.7.2. Out-of-Band Verification of Root-CA Key . . . . . . . 81
6.8. Certificate Request . . . . . . . . . . . . . . . . . . . 82
6.9. Key Update . . . . . . . . . . . . . . . . . . . . . . . 82
7. Version Negotiation . . . . . . . . . . . . . . . . . . . . . 82
7.1. Supporting RFC 2510 Implementations . . . . . . . . . . . 83
7.1.1. Clients Talking to RFC 2510 Servers . . . . . . . . . 83
7.1.2. Servers Receiving Version cmp1999 PKIMessages . . . . 83
8. Security Considerations . . . . . . . . . . . . . . . . . . . 83
8.1. On the Necessity of Proof-Of-Possession . . . . . . . . . 83
8.2. Proof-Of-Possession with a Decryption Key . . . . . . . . 84
8.3. Proof-Of-Possession by Exposing the Private Key . . . . . 84
8.4. Attack Against Diffie-Hellman Key Exchange . . . . . . . 85
8.5. Perfect Forward Secrecy . . . . . . . . . . . . . . . . . 85
8.6. Private Keys for Certificate Signing and CMP Message
Protection . . . . . . . . . . . . . . . . . . . . . . . 85
8.7. Entropy of Random Numbers, Key Pairs, and Shared Secret
Information . . . . . . . . . . . . . . . . . . . . . . 86
8.8. Recurring Usage of KEM Keys for Message Protection . . . 87
8.9. Trust Anchor Provisioning Using CMP Messages . . . . . . 87
8.10. Authorizing Requests for Certificates with Specific
EKUs . . . . . . . . . . . . . . . . . . . . . . . . . . 88
8.11. Usage of Certificate Transparency Logs . . . . . . . . . 88
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 88
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 89
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 89
11.1. Normative References . . . . . . . . . . . . . . . . . . 89
11.2. Informative References . . . . . . . . . . . . . . . . . 91
Appendix A. Reasons for the Presence of RAs . . . . . . . . . . 94
Appendix B. The Use of Revocation Passphrase . . . . . . . . . . 95
Appendix C. PKI Management Message Profiles (REQUIRED) . . . . . 97
C.1. General Rules for Interpretation of These Profiles. . . . 97
C.2. Algorithm Use Profile . . . . . . . . . . . . . . . . . . 98
C.3. Proof-of-Possession Profile . . . . . . . . . . . . . . . 98
C.4. Initial Registration/Certification (Basic Authenticated
Scheme) . . . . . . . . . . . . . . . . . . . . . . . . . 99
C.5. Certificate Request . . . . . . . . . . . . . . . . . . . 105
C.6. Key Update Request . . . . . . . . . . . . . . . . . . . 106
Appendix D. PKI Management Message Profiles (OPTIONAL) . . . . . 106
D.1. General Rules for Interpretation of These Profiles. . . . 107
D.2. Algorithm Use Profile . . . . . . . . . . . . . . . . . . 107
D.3. Self-Signed Certificates . . . . . . . . . . . . . . . . 107
D.4. Root CA Key Update . . . . . . . . . . . . . . . . . . . 108
D.5. PKI Information Request/Response . . . . . . . . . . . . 108
D.6. Cross Certification Request/Response (1-way) . . . . . . 110
D.7. In-Band Initialization Using External Identity
Certificate . . . . . . . . . . . . . . . . . . . . . . . 114
Appendix E. Variants of Using KEM Keys for PKI Message
Protection . . . . . . . . . . . . . . . . . . . . . . . 115
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Appendix F. Compilable ASN.1 Definitions . . . . . . . . . . . . 118
Appendix G. History of Changes . . . . . . . . . . . . . . . . . 133
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 137
1. Introduction
[RFC Editor: please delete:
During IESG telechat the CMP Updates document was approved on
condition that LAMPS provides a RFC4210bis document. Version -00 of
this document shall be identical to RFC 4210 and version -01
incorporates the changes specified in CMP Updates Section 2 and
Appendix A.2.
A history of changes is available in Appendix G of this document.
The authors of this document wish to thank Carlisle Adams, Stephen
Farrell, Tomi Kause, and Tero Mononen, the original authors of
RFC4210, for their work and invite them, next to further volunteers,
to join the -bis activity as co-authors.
]
[RFC Editor:
Please perform the following substitution.
* RFCXXXX --> the assigned numerical RFC value for this draft
* RFCDDDD --> the assigned numerical RFC value for
[I-D.ietf-lamps-rfc6712bis]
* RFCFFFF --> the assigned numerical RFC value for
[I-D.ietf-lamps-cms-kemri] ]
This document describes the Internet X.509 Public Key Infrastructure
(PKI) Certificate Management Protocol (CMP). Protocol messages are
defined for certificate creation and management. The term
"certificate" in this document refers to an X.509v3 Certificate as
defined in [ITU.X509.2000].
1.1. Changes Since RFC 2510
[RFC4210] differs from [RFC2510] in the following areas:
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* The PKI management message profile section is split to two
appendices: the required profile and the optional profile. Some
of the formerly mandatory functionality is moved to the optional
profile.
* The message confirmation mechanism has changed substantially.
* A new polling mechanism is introduced, deprecating the old polling
method at the CMP transport level.
* The CMP transport protocol issues are handled in a separate
document [I-D.ietf-lamps-rfc6712bis], thus the Transports section
is removed.
* A new implicit confirmation method is introduced to reduce the
number of protocol messages exchanged in a transaction.
* The new specification contains some less prominent protocol
enhancements and improved explanatory text on several issues.
1.2. Changes Since RFC 4210
CMP Updates [RFC9480] and CMP Algorithms [RFC9481] updated [RFC4210],
supporting the PKI management operations specified in the Lightweight
CMP Profile [RFC9483], in the following areas:
* Added new extended key usages for various CMP server types, e.g.,
registration authority and certification authority, to express the
authorization of the certificate holder that acts as the indicated
type of PKI management entity.
* Extended the description of multiple protection to cover
additional use cases, e.g., batch processing of messages.
* Use the type EnvelopedData as the preferred choice instead of
EncryptedValue to better support crypto agility in CMP.
For reasons of completeness and consistency, the type
EncryptedValue has been exchanged in all occurrences. This
includes the protection of centrally generated private keys,
encryption of certificates, proof-of-possession methods, and
protection of revocation passphrases. To properly differentiate
the support of EnvelopedData instead of EncryptedValue, CMP
version 3 is introduced in case a transaction is supposed to use
EnvelopedData.
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Note: According to [RFC4211], Section 2.1, point 9, the use of the
EncryptedValue structure has been deprecated in favor of the
EnvelopedData structure. [RFC4211] offers the EncryptedKey
structure a choice of EncryptedValue and EnvelopedData for
migration to EnvelopedData.
* Offer an optional hashAlg field in CertStatus supporting cases
that a certificate needs to be confirmed that has a signature
algorithm that does not indicate a specific hash algorithm to use
for computing the certHash. This is also in preparation for
upcoming post-quantum algorithms.
* Added new general message types to request CA certificates, a root
CA update, a certificate request template, or Certificate
Revocation List (CRL) updates.
* Extended the use of polling to p10cr, certConf, rr, genm, and
error messages.
* Deleted the mandatory algorithm profile in Appendix C.2 and refer
instead to Section 7 of [RFC9481].
* Added Section 8.6, Section 8.7, Section 8.9, and Section 8.10.
1.3. Changes Made by This Document
This document obsoletes [RFC4210] and [RFC9480]. It includes the
changes specified by Section 2 and Appendix C.2 of [RFC9480] as
described in Section 1.2. Additionally this document updates the
content of [RFC4210] in the following areas:
* Added Section 3.1.1.4 introducing the Key Generation Authority.
* Extended Section 3.1.2 regarding use of Certificate Transparency
logs.
* Updated Section 4.4.1 clarifying the definition of "new with new"
certificate validity period.
* Added Section 5.1.1.3 containing description of origPKIMessage
content moved here from Section 5.1.3.4.
* Added support for KEM keys for proof-of-possession to Section 4.3
and Section 5.2.8, for message protection to Section 5.1.1,
Section 5.1.3.4, and Appendix E, and for usage with CMS
EnvelopedData to Section 5.2.2.
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* Incorporated the request message behavioral clarifications from
Appendix C of [RFC4210] to Section 5. The definition of
altCertTemplate was incorporated into Section 5.2.1 and the
clarification on POPOSigningKey and on POPOPrivKey was
incorporated into Section 5.2.8.
* Added support support for CMS EnvelopedData to different proof-of-
possession methods for transferring encrypted private keys,
certificates, and challenges to Section 5.2.8.
* Added Section 8.1, Section 8.5, Section 8.8, and Section 8.11.
2. Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. PKI Management Overview
The PKI must be structured to be consistent with the types of
individuals who must administer it. Providing such administrators
with unbounded choices not only complicates the software required,
but also increases the chances that a subtle mistake by an
administrator or software developer will result in broader
compromise. Similarly, restricting administrators with cumbersome
mechanisms will cause them not to use the PKI.
Management protocols are REQUIRED to support on-line interactions
between Public Key Infrastructure (PKI) components. For example, a
management protocol might be used between a Certification Authority
(CA) and a client system with which a key pair is associated, or
between two CAs that issue cross-certificates for each other.
3.1. PKI Management Model
Before specifying particular message formats and procedures, we first
define the entities involved in PKI management and their interactions
(in terms of the PKI management functions required). We then group
these functions in order to accommodate different identifiable types
of end entities.
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3.1.1. Definitions of PKI Entities
The entities involved in PKI management include the end entity (i.e.,
the entity to whom the certificate is issued) and the certification
authority (i.e., the entity that issues the certificate). A
registration authority MAY also be involved in PKI management.
3.1.1.1. Subjects and End Entities
The term "subject" is used here to refer to the entity to whom the
certificate is issued, typically named in the subject or
subjectAltName field of a certificate. When we wish to distinguish
the tools and/or software used by the subject (e.g., a local
certificate management module), we will use the term "subject
equipment". In general, the term "end entity" (EE), rather than
"subject", is preferred in order to avoid confusion with the field
name. It is important to note that the end entities here will
include not only human users of applications, but also applications
themselves (e.g., for IP security) or devices (e.g., routers or
industrial control systems). This factor influences the protocols
that the PKI management operations use; for example, application
software is far more likely to know exactly which certificate
extensions are required than are human users. PKI management
entities are also end entities in the sense that they are sometimes
named in the subject or subjectAltName field of a certificate or
cross-certificate. Where appropriate, the term "end entity" will be
used to refer to end entities who are not PKI management entities.
All end entities require secure local access to some information --
at a minimum, their own name and private key, the name of a CA that
is directly trusted by this entity, and that CA's public key (or a
fingerprint of the public key where a self-certified version is
available elsewhere). Implementations MAY use secure local storage
for more than this minimum (e.g., the end entity's own certificates
or application-specific information). The form of storage will also
vary -- from files to tamper-resistant cryptographic tokens. The
information stored in such local, trusted storage is referred to here
as the end entity's Personal Security Environment (PSE).
Though PSE formats are beyond the scope of this document (they are
very dependent on equipment, et cetera), a generic interchange format
for PSEs is defined here: a certification response message MAY be
used.
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3.1.1.2. Certification Authority
The certification authority (CA) may or may not actually be a real
"third party" from the end entity's point of view. Quite often, the
CA will actually belong to the same organization as the end entities
it supports.
Again, we use the term "CA" to refer to the entity named in the
issuer field of a certificate. When it is necessary to distinguish
the software or hardware tools used by the CA, we use the term "CA
equipment".
The CA equipment will often include both an "off-line" component and
an "on-line" component, with the CA private key only available to the
"off-line" component. This is, however, a matter for implementers
(though it is also relevant as a policy issue).
We use the term "root CA" to indicate a CA that is directly trusted
by an end entity; that is, securely acquiring the value of a root CA
public key requires some out-of-band step(s). This term is not meant
to imply that a root CA is necessarily at the top of any hierarchy,
simply that the CA in question is trusted directly.
A "subordinate CA" is one that is not a root CA for the end entity in
question. Often, a subordinate CA will not be a root CA for any
entity, but this is not mandatory.
3.1.1.3. Registration Authority
In addition to end-entities and CAs, many environments call for the
existence of a Registration Authority (RA) separate from the
Certification Authority. The functions that the registration
authority may carry out will vary from case to case but MAY include
personal authentication, token distribution, checking certificate
requests and authentication of their origin, revocation reporting,
name assignment, key generation, archival of key pairs, et cetera.
This document views the RA as an OPTIONAL component: when it is not
present, the CA is assumed to be able to carry out the RA's functions
so that the PKI management protocols are the same from the end-
entity's point of view.
Again, we distinguish, where necessary, between the RA and the tools
used (the "RA equipment").
Note that an RA is itself an end entity. We further assume that all
RAs are in fact certified end entities and that RAs have private keys
that are usable for signing. How a particular CA equipment
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identifies some end entities as RAs is an implementation issue (i.e.,
this document specifies no special RA certification operation). We
do not mandate that the RA is certified by the CA with which it is
interacting at the moment (so one RA may work with more than one CA
whilst only being certified once).
In some circumstances, end entities will communicate directly with a
CA even where an RA is present. For example, for initial
registration and/or certification, the end entity may use its RA, but
communicate directly with the CA in order to refresh its certificate.
3.1.1.4. Key Generation Authority
A Key Generation Authority (KGA) is a PKI management entity
generating key pairs on behalf of an end entity. As the KGA
generates the key pair it knows the public and the private part.
This document views the KGA as an OPTIONAL component. When it is not
present and central key generation is needed, the CA is assumed to be
able to carry out the KGA's functions so that the PKI management
protocol messages are the same from the end-entity's point of view.
If certain tasks of a CA are delegated to other components, this
delegation needs authorization, which can be indicated by extended
key usages (see Section 4.5).
Note: When doing central generation of key pairs, implementers should
consider the implications of server-side retention on the overall
security of the system; in some case retention is good, for example
for escrow reasons, but in other cases the server should clear its
copy after delivery to the end entity.
3.1.2. PKI Management Requirements
The protocols given here meet the following requirements on PKI
management
1. PKI management must conform to the ISO/IEC 9594-8/ITU-T X.509
standards.
2. It must be possible to regularly update any key pair without
affecting any other key pair.
3. The use of confidentiality in PKI management protocols must be
kept to a minimum in order to ease acceptance in environments
where strong confidentiality might cause regulatory problems.
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4. PKI management protocols must allow the use of different
industry-standard cryptographic algorithms, see CMP Algorithms
[RFC9481]. This means that any given CA, RA, or end entity may,
in principle, use whichever algorithms suit it for its own key
pair(s).
5. PKI management protocols must not preclude the generation of key
pairs by the end entity concerned, by a KGA, by an RA, or by a
CA. Key generation may also occur elsewhere, but for the
purposes of PKI management we can regard key generation as
occurring wherever the key is first present at an end entity,
RA, or CA.
6. PKI management protocols must support the publication of
certificates by the end entity concerned, by an RA, or by a CA.
Different implementations and different environments may choose
any of the above approaches.
7. PKI management protocols must support the production of
Certificate Revocation Lists (CRLs) by allowing certified end
entities to make requests for the revocation of certificates.
This must be done in such a way that the denial-of-service
attacks, which are possible, are not made simpler.
8. PKI management protocols must be usable over a variety of
"transport" mechanisms, specifically including mail, HTTP, TCP/
IP, CoAP, and off-line file-based.
9. Final authority for certification creation rests with the CA.
No RA or end entity equipment can assume that any certificate
issued by a CA will contain what was requested; a CA may alter
certificate field values or may add, delete, or alter extensions
according to its operating policy. In other words, all PKI
entities (end-entities, RAs, and CAs) must be capable of
handling responses to requests for certificates in which the
actual certificate issued is different from that requested (for
example, a CA may shorten the validity period requested). Note
that policy may dictate that the CA must not publish or
otherwise distribute the certificate until the requesting entity
has reviewed and accepted the newly-created certificate or the
POP is completed. In case of publication of the certificate
(when using indirect POP, see Section 8.11) or a precertificate
in a Certificate Transparency log [RFC9162], the certificate
must be revoked if it was not accepted by the EE or the POP
could not be completed.
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10. A graceful, scheduled change-over from one non-compromised CA
key pair to the next (CA key update) must be supported (note
that if the CA key is compromised, re-initialization must be
performed for all entities in the domain of that CA). An end
entity whose PSE contains the new CA public key (following a CA
key update) must also be able to verify certificates verifiable
using the old public key. End entities who directly trust the
old CA key pair must also be able to verify certificates signed
using the new CA private key (required for situations where the
old CA public key is "hardwired" into the end entity's
cryptographic equipment).
11. The functions of an RA may, in some implementations or
environments, be carried out by the CA itself. The protocols
must be designed so that end entities will use the same protocol
regardless of whether the communication is with an RA or CA.
Naturally, the end entity must use the correct RA or CA public
key to protect the communication.
12. Where an end entity requests a certificate containing a given
public key value, the end entity must be ready to demonstrate
possession of the corresponding private key value. This may be
accomplished in various ways, depending on the type of
certification request. See Section 4.3 for details of the in-
band methods defined for the PKIX-CMP (i.e., Certificate
Management Protocol) messages.
3.1.3. PKI Management Operations
The following diagram shows the relationship between the entities
defined above in terms of the PKI management operations. The letters
in the diagram indicate "protocols" in the sense that a defined set
of PKI management messages can be sent along each of the lettered
lines.
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+---+ cert. publish +------------+ j
| | <--------------------- | End Entity | <-------
| C | g +------------+ "out-of-band"
| e | | ^ loading
| r | | | initial
| t | a | | b registration/
| | | | certification
| / | | | key pair recovery
| | | | key pair update
| C | | | certificate update
| R | PKI "USERS" V | revocation request
| L | -------------------+-+-----+-+------+-+-------------------
| | PKI MANAGEMENT | ^ | ^
| | ENTITIES a | | b a | | b
| R | V | | |
| e | g +------+ d | |
| p | <------------ | RA | <-----+ | |
| o | cert. | | ----+ | | |
| s | publish +------+ c | | | |
| i | | | | |
| t | V | V |
| o | g +------------+ i
| r | <------------------------| CA |------->
| y | h +------------+ "out-of-band"
| | cert. publish | ^ publication
| | CRL publish | |
+---+ | | cross-certification
e | | f cross-certificate
| | update
| |
V |
+------+
| CA-2 |
+------+
Figure 1: PKI Entities
At a high level, the set of operations for which management messages
are defined can be grouped as follows.
1. CA establishment: When establishing a new CA, certain steps are
required (e.g., production of initial CRLs, export of CA public
key).
2. End entity initialization: this includes importing a root CA
public key and requesting information about the options supported
by a PKI management entity.
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3. Certification: various operations result in the creation of new
certificates:
1. initial registration/certification: This is the process
whereby an end entity first makes itself known to a CA or RA,
prior to the CA issuing a certificate or certificates for
that end entity. The end result of this process (when it is
successful) is that a CA issues a certificate for an end
entity's public key, and returns that certificate to the end
entity and/or posts that certificate in a public repository.
This process may, and typically will, involve multiple
"steps", possibly including an initialization of the end
entity's equipment. For example, the end entity's equipment
must be securely initialized with the public key of a CA, to
be used in validating certificate paths. Furthermore, an end
entity typically needs to be initialized with its own key
pair(s).
2. key pair update: Every key pair needs to be updated regularly
(i.e., replaced with a new key pair), and a new certificate
needs to be issued.
3. certificate update: As certificates expire, they may be
"refreshed" if nothing relevant in the environment has
changed.
4. CA key pair update: As with end entities, CA key pairs need
to be updated regularly; however, different mechanisms are
required.
5. cross-certification request: One CA requests issuance of a
cross-certificate from another CA. For the purposes of this
standard, the following terms are defined. A "cross-
certificate" is a certificate in which the subject CA and the
issuer CA are distinct and SubjectPublicKeyInfo contains a
verification key (i.e., the certificate has been issued for
the subject CA's signing key pair). When it is necessary to
distinguish more finely, the following terms may be used: a
cross-certificate is called an "inter-domain cross-
certificate" if the subject and issuer CAs belong to
different administrative domains; it is called an "intra-
domain cross-certificate" otherwise.
1. Note 1. The above definition of "cross-certificate"
aligns with the defined term "CA-certificate" in X.509.
Note that this term is not to be confused with the X.500
"cACertificate" attribute type, which is unrelated.
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2. Note 2. In many environments, the term "cross-
certificate", unless further qualified, will be
understood to be synonymous with "inter-domain cross-
certificate" as defined above.
3. Note 3. Issuance of cross-certificates may be, but is
not necessarily, mutual; that is, two CAs may issue
cross-certificates for each other.
6. cross-certificate update: Similar to a normal certificate
update, but involving a cross-certificate.
4. Certificate/CRL discovery operations: some PKI management
operations result in the publication of certificates or CRLs:
1. certificate publication: Having gone to the trouble of
producing a certificate, some means for publishing it is
needed. The "means" defined in PKIX MAY involve the messages
specified in Sections 5.3.13 to 5.3.16, or MAY involve other
methods (LDAP, for example) as described in [RFC4511],
[RFC2585] (the "Operational Protocols" documents of the PKIX
series of specifications).
2. CRL publication: As for certificate publication.
5. Recovery operations: some PKI management operations are used when
an end entity has "lost" its PSE:
1. key pair recovery: As an option, user client key materials
(e.g., a user's private key used for decryption purposes) MAY
be backed up by a CA, an RA, or a key backup system
associated with a CA or RA. If an entity needs to recover
these backed up key materials (e.g., as a result of a
forgotten password or a lost key chain file), a protocol
exchange may be needed to support such recovery.
6. Revocation operations: some PKI management operations result in
the creation of new CRL entries and/or new CRLs:
1. revocation request: An authorized person advises a CA of an
abnormal situation requiring certificate revocation.
7. PSE operations: whilst the definition of PSE operations (e.g.,
moving a PSE, changing a PIN, etc.) are beyond the scope of this
specification, we do define a PKIMessage (CertRepMessage) that
can form the basis of such operations.
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Note that on-line protocols are not the only way of implementing the
above operations. For all operations, there are off-line methods of
achieving the same result, and this specification does not mandate
use of on-line protocols. For example, when hardware tokens are
used, many of the operations MAY be achieved as part of the physical
token delivery.
Later sections define a set of standard messages supporting the above
operations. Transport protocols for conveying these exchanges in
different environments (e.g., off-line: file-based, on-line: mail,
HTTP [I-D.ietf-lamps-rfc6712bis], and CoAP [RFC9482]) are beyond the
scope of this document and are specified separately.
4. Assumptions and Restrictions
4.1. End Entity Initialization
The first step for an end entity in dealing with PKI management
entities is to request information about the PKI functions supported
and to securely acquire a copy of the relevant root CA public key(s).
4.2. Initial Registration/Certification
There are many schemes that can be used to achieve initial
registration and certification of end entities. No one method is
suitable for all situations due to the range of policies that a CA
may implement and the variation in the types of end entity which can
occur.
However, we can classify the initial registration/certification
schemes that are supported by this specification. Note that the word
"initial", above, is crucial: we are dealing with the situation where
the end entity in question has had no previous contact with the PKI.
Where the end entity already possesses certified keys, then some
simplifications/alternatives are possible.
Having classified the schemes that are supported by this
specification we can then specify some as mandatory and some as
optional. The goal is that the mandatory schemes cover a sufficient
number of the cases that will arise in real use, whilst the optional
schemes are available for special cases that arise less frequently.
In this way, we achieve a balance between flexibility and ease of
implementation.
We will now describe the classification of initial registration/
certification schemes.
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4.2.1. Criteria Used
4.2.1.1. Initiation of Registration/Certification
In terms of the PKI messages that are produced, we can regard the
initiation of the initial registration/certification exchanges as
occurring wherever the first PKI message relating to the end entity
is produced. Note that the real-world initiation of the
registration/certification procedure may occur elsewhere (e.g., a
personnel department may telephone an RA operator).
The possible locations are at the end entity, an RA, or a CA.
4.2.1.2. End Entity Message Origin Authentication
The on-line messages produced by the end entity that requires a
certificate may be authenticated or not. The requirement here is to
authenticate the origin of any messages from the end entity to the
PKI (CA/RA).
In this specification, such authentication is achieved by two
different means:
* symmetric: The PKI (CA/RA) issuing the end entity with a secret
value (initial authentication key) and reference value (used to
identify the secret value) via some out-of-band means. The
initial authentication key can then be used to protect relevant
PKI messages.
* asymmetric: Using a private key and certificate issued by another
PKI trusted for initial authentication, e.g., an IDevID
IEEE 802.1AR [IEEE.802.1AR-2018]. The trust establishment in this
external PKI is out of scope of this document.
Thus, we can classify the initial registration/certification scheme
according to whether or not the on-line end entity -> PKI messages
are authenticated or not.
Note 1: We do not discuss the authentication of the PKI -> end entity
messages here, as this is always REQUIRED. In any case, it can be
achieved simply once the root-CA public key has been installed at the
end entity's equipment or it can be based on the initial
authentication key.
Note 2: An initial registration/certification procedure can be secure
where the messages from the end entity are authenticated via some
out-of-band means (e.g., a subsequent visit).
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4.2.1.3. Location of Key Generation
In this specification, "key generation" is regarded as occurring
wherever either the public or private component of a key pair first
occurs in a PKIMessage. Note that this does not preclude a
centralized key generation service by a KGA; the actual key pair MAY
have been generated elsewhere and transported to the end entity, RA,
or CA using a (proprietary or standardized) key generation request/
response protocol (outside the scope of this specification).
Thus, there are three possibilities for the location of "key
generation": the end entity, an RA, or a CA.
4.2.1.4. Confirmation of Successful Certification
Following the creation of an initial certificate for an end entity,
additional assurance can be gained by having the end entity
explicitly confirm successful receipt of the message containing (or
indicating the creation of) the certificate. Naturally, this
confirmation message must be protected (based on the initial
symmetric or asymmetric authentication key or other means).
This gives two further possibilities: confirmed or not.
4.2.2. Mandatory Schemes
The criteria above allow for a large number of initial registration/
certification schemes. This specification mandates that conforming
CA equipment, RA equipment, and EE equipment MUST support the second
scheme listed below (Section 4.2.2.2). Any entity MAY additionally
support other schemes, if desired.
4.2.2.1. Centralized Scheme
In terms of the classification above, this scheme is, in some ways,
the simplest possible, where:
* initiation occurs at the certifying CA;
* no on-line message authentication is required;
* "key generation" occurs at the certifying CA (see
Section 4.2.1.3);
* no confirmation message is required.
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In terms of message flow, this scheme means that the only message
required is sent from the CA to the end entity. The message must
contain the entire PSE for the end entity. Some out-of-band means
must be provided to allow the end entity to authenticate the message
received and to decrypt any encrypted values.
4.2.2.2. Basic Authenticated Scheme
In terms of the classification above, this scheme is where:
* initiation occurs at the end entity;
* message authentication is REQUIRED;
* "key generation" occurs at the end entity (see Section 4.2.1.3);
* a confirmation message is REQUIRED.
Note: An Initial Authentication Key (IAK) can be either a symmetric
key or an asymmetric private key with a certificate issued by another
PKI trusted for this purpose. The establishment of such trust is out
of scope of this document.
In terms of message flow, the basic authenticated scheme is as
follows:
End entity RA/CA
========== =============
out-of-band distribution of Initial Authentication
Key (IAK) and reference value (RA/CA -> EE)
Key generation
Creation of certification request
Protect request with IAK
-->>-- certification request -->>--
verify request
process request
create response
--<<-- certification response --<<--
handle response
create confirmation
-->>-- cert conf message -->>--
verify confirmation
create response
--<<-- conf ack (optional) --<<--
handle response
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(Where verification of the cert confirmation message fails, the RA/CA
MUST revoke the newly issued certificate if it has been published or
otherwise made available.)
4.3. Proof-of-Possession (POP) of Private Key
Proof-of-possession (POP) is where a PKI management entity (CA/RA)
verifies if an end entity has access to the private key corresponding
to a given public key. The question of whether, and in what
circumstances, POPs add value to a PKI is a debate as old as PKI
itself! See Section 8.1 for a further discussion on the necessity of
proof-of-possession in PKI.
The PKI management operations specified here make it possible for an
end entity to prove to a CA/RA that it has possession of (i.e., is
able to use) the private key corresponding to the public key for
which a certificate is requested (see Section 5.2.8 for different POP
methods). A given CA/RA is free to choose how to enforce POP (e.g.,
out-of-band procedural means versus PKIX-CMP in-band messages) in its
certification exchanges (i.e., this may be a policy issue). However,
it is REQUIRED that CAs/RAs MUST enforce POP by some means because
there are currently many non-PKIX operational protocols in use
(various electronic mail protocols are one example) that do not
explicitly check the binding between the end entity and the private
key. Until operational protocols that do verify the binding (for
signature, encryption, key agreement, and KEM key pairs) exist, and
are ubiquitous, this binding can only be assumed to have been
verified by the CA/RA. Therefore, if the binding is not verified by
the CA/RA, certificates in the Internet Public-Key Infrastructure end
up being somewhat less meaningful.
POP is accomplished in different ways depending upon the type of key
for which a certificate is requested. If a key can be used for
multiple purposes (e.g., an RSA key) then any appropriate method MAY
be used (e.g., a key that may be used for signing, as well as other
purposes, SHOULD NOT be sent to the CA/RA in order to prove
possession).
This specification explicitly allows for cases where an end entity
supplies the relevant proof to an RA and the RA subsequently attests
to the CA that the required proof has been received (and validated!).
For example, an end entity wishing to have a signing key certified
could send the appropriate signature to the RA, which then simply
notifies the relevant CA that the end entity has supplied the
required proof. Of course, such a situation may be disallowed by
some policies (e.g., CAs may be the only entities permitted to verify
POP during certification).
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4.3.1. Signature Keys
For signature keys, the end entity can sign a value to prove
possession of the private key.
4.3.2. Encryption Keys
For encryption keys, the end entity can provide the private key to
the CA/RA (e.g., for archiving), or can be required to decrypt a
value in order to prove possession of the private key. Decrypting a
value can be achieved either directly or indirectly.
The direct method is for the RA/CA to issue a random challenge to
which an immediate response by the EE is required.
The indirect method is to issue a certificate that is encrypted for
the end entity (and have the end entity demonstrate its ability to
decrypt this certificate in the confirmation message). This allows a
CA to issue a certificate in a form that can only be used by the
intended end entity.
This specification encourages use of the indirect method because it
requires no extra messages to be sent (i.e., the proof can be
demonstrated using the {request, response, confirmation} triple of
messages).
4.3.3. Key Agreement Keys
For key agreement keys, the end entity and the PKI management entity
(i.e., CA or RA) must establish a shared secret key in order to prove
that the end entity has possession of the private key.
Note that this need not impose any restrictions on the keys that can
be certified by a given CA. In particular, for Diffie-Hellman keys
the end entity may freely choose its algorithm parameters provided
that the CA can generate a short-term (or one-time) key pair with the
appropriate parameters when necessary.
4.3.4. Key Encapsulation Mechanism Keys
For key encapsulation mechanism (KEM) keys, the end entity can
provide the private key to the CA/RA (e.g., for archiving), or can be
required to decrypt a value in order to prove possession of the
private key. Decrypting a value can be achieved either directly or
indirectly.
Note: A definition of key encapsulation mechanisms can be found in
[I-D.ietf-lamps-cms-kemri], Section 1.
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The direct method is for the RA/CA to issue a random challenge to
which an immediate response by the EE is required.
The indirect method is to issue a certificate that is encrypted for
the end entity using a shared secret key derived from a key
encapsulated using the public key (and have the end entity
demonstrate its ability to use its private key for decapsulation of
the KEM ciphertext, derive the shared secret key, decrypt this
certificate, and provide a hash of the certificate in the
confirmation message). This allows a CA to issue a certificate in a
form that can only be used by the intended end entity.
This specification encourages use of the indirect method because it
requires no extra messages to be sent (i.e., the proof can be
demonstrated using the {request, response, confirmation} triple of
messages).
A certification request message for a KEM certificate SHALL use
POPOPrivKey by using the keyEncipherment choice of ProofOfPossession,
see Section 5.2.8, in the popo field of CertReqMsg as long as no KEM-
specific choice is available.
4.4. Root CA Key Update
This discussion only applies to CAs that are directly trusted by some
end entities. Self-signed CAs SHALL be considered as directly
trusted CAs. Recognizing whether a non-self-signed CA is supposed to
be directly trusted for some end entities is a matter of CA policy
and is thus beyond the scope of this document.
The basis of the procedure described here is that the CA protects its
new public key using its previous private key and vice versa. Thus,
when a CA updates its key pair it must generate two extra
cACertificate attribute values if certificates are made available
using an X.500 directory (for a total of four: OldWithOld,
OldWithNew, NewWithOld, and NewWithNew).
When a CA changes its key pair, those entities who have acquired the
old CA public key via "out-of-band" means are most affected. It is
these end entities who will need access to the new CA public key
protected with the old CA private key. However, they will only
require this for a limited period (until they have acquired the new
CA public key via the "out-of-band" mechanism). This will typically
be easily achieved when these end entities' certificates expire.
The data structure used to protect the new and old CA public keys is
a standard certificate (which may also contain extensions). There
are no new data structures required.
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Note 1: This scheme does not make use of any of the X.509 v3
extensions as it must be able to work even for version 1
certificates. The presence of the KeyIdentifier extension would make
for efficiency improvements.
Note 2:. While the scheme could be generalized to cover cases where
the CA updates its key pair more than once during the validity period
of one of its end entities' certificates, this generalization seems
of dubious value. Not having this generalization simply means that
the validity periods of certificates issued with the old CA key pair
cannot exceed the end of the OldWithNew validity period.
Note 3: This scheme ensures that end entities will acquire the new CA
public key, at the latest by the expiry of the last certificate they
owned that was signed with the old CA private key (via the "out-of-
band" means). Certificate and/or key update operations occurring at
other times do not necessarily require this (depending on the end
entity's equipment).
Note 4: In practice, a new root CA may have a slightly different
subject DN, e.g., indicating a generation identifier like the year of
issuance or a version number, for instance in an OU element. How to
bridge trust to the new root CA certificate in a CA DN change or a
cross-certificate scenario is out of scope for this document.
4.4.1. CA Operator Actions
To change the key of the CA, the CA operator does the following:
1. Generate a new key pair;
2. Create a certificate containing the old CA public key signed with
the new private key (the "old with new" certificate);
3. Create a certificate containing the new CA public key signed with
the old private key (the "new with old" certificate);
4. Create a certificate containing the new CA public key signed with
the new private key (the "new with new" certificate);
5. Publish these new certificates via the repository and/or other
means (perhaps using a CAKeyUpdAnn message or
RootCaKeyUpdateContent);
6. Export the new CA public key so that end entities may acquire it
using the "out-of-band" mechanism (if required).
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The old CA private key is then no longer required. However, the old
CA public key will remain in use for some time. The old CA public
key is no longer required (other than for non-repudiation) when all
end entities of this CA have securely acquired the new CA public key.
The "old with new" certificate must have a validity period with the
same notBefore and notAfter time as the "old with old" certificate.
The "new with old" certificate must have a validity period with the
same notBefore time as the "new with new" certificate and a notAfter
time by which all end entities of this CA will securely possess the
new CA public key (at the latest, at the notAfter time of the "old
with old" certificate).
The "new with new" certificate must have a validity period with a
notBefore time that is before the notAfter time of the "old with old"
certificate and a notAfter time that is after the notBefore time of
the next update of this certificate.
Note: Further operational considerations on transition from one root
CA self-signed certificate to the next is available in RFC 8649
Section 5 [RFC8649].
4.4.2. Verifying Certificates
Normally when verifying a signature, the verifier verifies (among
other things) the certificate containing the public key of the
signer. However, once a CA is allowed to update its key there are a
range of new possibilities. These are shown in the table below.
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Repository contains NEW Repository contains only OLD
and OLD public keys public key (due to, e.g.,
delay in publication)
PSE PSE Contains PSE Contains PSE Contains
Contains OLD public NEW public OLD public
NEW public key key key
key
Signer's Case 1: Case 3: Case 5: Case 7:
certifi- This is In this case Although the In this case
cate is the the verifier CA operator the CA
protected standard must access has not operator has
using NEW case where the updated the not updated
key pair the repository in repository the the repository
verifier order to get verifier can and so the
can the value of verify the verification
directly the NEW certificate will FAIL
verify the public key directly -
certificate this is thus
without the same as
using the case 1.
repository
Signer's Case 2: Case 4: Case 6: Case 8:
certifi- In this In this case The verifier Although the
cate is case the the verifier thinks this CA operator
protected verifier can directly is the has not
using OLD must verify the situation of updated the
key pair access the certificate case 2 and repository the
repository without will access verifier can
in order using the the verify the
to get the repository repository; certificate
value of however, the directly -
the OLD verification this is thus
public key will FAIL the same as
case 4.
Note: Instead of using a repository, the end entity can use the root
CA update general message to request the respective certificates from
a PKI management entity, see Section 5.3.19.15, and follow the
required validation steps.
4.4.2.1. Verification in Cases 1, 4, 5, and 8
In these cases, the verifier has a local copy of the CA public key
that can be used to verify the certificate directly. This is the
same as the situation where no key change has occurred.
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Note that case 8 may arise between the time when the CA operator has
generated the new key pair and the time when the CA operator stores
the updated attributes in the repository. Case 5 can only arise if
the CA operator has issued both the signer's and verifier's
certificates during this "gap" (the CA operator SHOULD avoid this as
it leads to the failure cases described below)
4.4.2.2. Verification in Case 2
In case 2, the verifier must get access to the old public key of the
CA. The verifier does the following:
1. Look up the caCertificate attribute in the repository and pick
the OldWithNew certificate (determined based on validity periods;
note that the subject and issuer fields must match);
2. Verify that this is correct using the new CA key (which the
verifier has locally);
3. If correct, check the signer's certificate using the old CA key.
Case 2 will arise when the CA operator has issued the signer's
certificate, then changed the key, and then issued the verifier's
certificate; so it is quite a typical case.
4.4.2.3. Verification in Case 3
In case 3, the verifier must get access to the new public key of the
CA. In case a repository is used, the verifier does the following:
1. Look up the cACertificate attribute in the repository and pick
the NewWithOld certificate (determined based on validity periods;
note that the subject and issuer fields must match);
2. Verify that this is correct using the old CA key (which the
verifier has stored locally);
3. If correct, check the signer's certificate using the new CA key.
Case 3 will arise when the CA operator has issued the verifier's
certificate, then changed the key, and then issued the signer's
certificate; so it is also quite a typical case.
Note: Alternatively, the verifier can use the root CA update general
message to request the respective certificates from a PKI management
entity, see Section 5.3.19.15, and follow the required validation
steps.
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4.4.2.4. Failure of Verification in Case 6
In this case, the CA has issued the verifier's PSE, which contains
the new key, without updating the repository attributes. This means
that the verifier has no means to get a trustworthy version of the
CA's old key and so verification fails.
Note that the failure is the CA operator's fault.
4.4.2.5. Failure of Verification in Case 7
In this case, the CA has issued the signer's certificate protected
with the new key without updating the repository attributes. This
means that the verifier has no means to get a trustworthy version of
the CA's new key and so verification fails.
Note that the failure is again the CA operator's fault.
4.4.3. Revocation - Change of CA Key
As we saw above, the verification of a certificate becomes more
complex once the CA is allowed to change its key. This is also true
for revocation checks as the CA may have signed the CRL using a newer
private key than the one within the user's PSE.
The analysis of the alternatives is the same as for certificate
verification.
4.5. Extended Key Usage for PKI Entities
The extended key usage (EKU) extension indicates the purposes for
which the certified key pair may be used. Therefore, it restricts
the use of a certificate to specific applications.
A CA may want to delegate parts of its duties to other PKI management
entities. This section provides a mechanism to both prove this
delegation and enable automated means for checking the authorization
of this delegation. Such delegation may also be expressed by other
means, e.g., explicit configuration.
To offer automatic validation for the delegation of a role by a CA to
another entity, the certificates used for CMP message protection or
signed data for central key generation MUST be issued by the
delegating CA and MUST contain the respective EKUs. This proves that
the delegating CA authorized this entity to act in the given role, as
described below.
The OIDs to be used for these EKUs are:
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id-kp-cmcCA OBJECT IDENTIFIER ::= {
iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) kp(3) 27 }
id-kp-cmcRA OBJECT IDENTIFIER ::= {
iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) kp(3) 28 }
id-kp-cmKGA OBJECT IDENTIFIER ::= {
iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) kp(3) 32 }
Note: Section 2.10 of [RFC6402] specifies OIDs for a Certificate
Management over CMS (CMC) CA and a CMC RA. As the functionality of a
CA and RA is not specific to any certificate management protocol
(such as CMC or CMP), these EKUs are reused by CMP.
The meaning of the id-kp-cmKGA EKU is as follows:
CMP KGA: CMP key generation authorities are CAs or are identified by
the id-kp-cmKGA extended key usage. The CMP KGA knows the
private key it generated on behalf of the end entity. This
is a very sensitive service and needs specific
authorization, which by default is with the CA certificate
itself. The CA may delegate its authorization by placing
the id-kp-cmKGA extended key usage in the certificate used
to authenticate the origin of the generated private key.
The authorization may also be determined through local
configuration of the end entity.
5. Data Structures
This section contains descriptions of the data structures required
for PKI management messages. Section 6 describes constraints on
their values and the sequence of events for each of the various PKI
management operations.
5.1. Overall PKI Message
All of the messages used in this specification for the purposes of
PKI management use the following structure:
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PKIMessage ::= SEQUENCE {
header PKIHeader,
body PKIBody,
protection [0] PKIProtection OPTIONAL,
extraCerts [1] SEQUENCE SIZE (1..MAX) OF CMPCertificate
OPTIONAL
}
PKIMessages ::= SEQUENCE SIZE (1..MAX) OF PKIMessage
The PKIHeader contains information that is common to many PKI
messages.
The PKIBody contains message-specific information.
The PKIProtection, when used, contains bits that protect the PKI
message.
The extraCerts field can contain certificates that may be useful to
the recipient. For example, this can be used by a CA or RA to
present an end entity with certificates that it needs to verify its
own new certificate (if, for example, the CA that issued the end
entity's certificate is not a root CA for the end entity). Note that
this field does not necessarily contain a certification path; the
recipient may have to sort, select from, or otherwise process the
extra certificates in order to use them.
5.1.1. PKI Message Header
All PKI messages require some header information for addressing and
transaction identification. Some of this information will also be
present in a transport-specific envelope. However, if the PKI
message is protected, then this information is also protected (i.e.,
we make no assumption about secure transport).
The following data structure is used to contain this information:
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PKIHeader ::= SEQUENCE {
pvno INTEGER { cmp1999(1), cmp2000(2),
cmp2021(3) },
sender GeneralName,
recipient GeneralName,
messageTime [0] GeneralizedTime OPTIONAL,
protectionAlg [1] AlgorithmIdentifier{ALGORITHM, {...}}
OPTIONAL,
senderKID [2] KeyIdentifier OPTIONAL,
recipKID [3] KeyIdentifier OPTIONAL,
transactionID [4] OCTET STRING OPTIONAL,
senderNonce [5] OCTET STRING OPTIONAL,
recipNonce [6] OCTET STRING OPTIONAL,
freeText [7] PKIFreeText OPTIONAL,
generalInfo [8] SEQUENCE SIZE (1..MAX) OF
InfoTypeAndValue OPTIONAL
}
PKIFreeText ::= SEQUENCE SIZE (1..MAX) OF UTF8String
The usage of the protocol version number (pvno) is described in
Section 7.
The sender field contains the name of the sender of the PKIMessage.
This name (in conjunction with senderKID, if supplied) should be
sufficient to indicate the key to use to verify the protection on the
message. If nothing about the sender is known to the sending entity
(e.g., in the init. req. message, where the end entity may not know
its own Distinguished Name (DN), e-mail name, IP address, etc.), then
the "sender" field MUST contain a "NULL" value; that is, the SEQUENCE
OF relative distinguished names is of zero length. In such a case,
the senderKID field MUST hold an identifier (i.e., a reference
number) that indicates to the receiver the appropriate shared secret
information to use to verify the message.
The recipient field contains the name of the recipient of the
PKIMessage. This name (in conjunction with recipKID, if supplied)
should be usable to verify the protection on the message.
The protectionAlg field specifies the algorithm used to protect the
message. If no protection bits are supplied (note that PKIProtection
is OPTIONAL) then this field MUST be omitted; if protection bits are
supplied, then this field MUST be supplied.
senderKID and recipKID are usable to indicate which keys have been
used to protect the message (recipKID will normally only be required
where protection of the message uses Diffie-Hellman (DH) or
elliptic curve Diffie-Hellman (ECDH) keys). These fields MUST be
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used if required to uniquely identify a key (e.g., if more than one
key is associated with a given sender name). The senderKID SHOULD be
used in any case.
Note: The recommendation of using senderKID was changed since
[RFC4210], where it was recommended to be omitted if not needed to
identify the protection key.
The transactionID field within the message header is to be used to
allow the recipient of a message to correlate this with an ongoing
transaction. This is needed for all transactions that consist of
more than just a single request/response pair. For transactions that
consist of a single request/response pair, the rules are as follows.
A client MUST populate the transactionID field if the message
contains an infoValue of type KemCiphertextInfo, see Section 5.1.3.4.
In all other cases the client MAY populate the transactionID field of
the request. If a server receives such a request that has the
transactionID field set, then it MUST set the transactionID field of
the response to the same value. If a server receives such request
with a missing transactionID field, then it MUST populate the
transactionID field if the message contains a KemCiphertextInfo
field. In all other cases the server MAY set transactionID field of
the response.
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For transactions that consist of more than just a single request/
response pair, the rules are as follows. Clients SHOULD generate a
transactionID for the first request. If a server receives such a
request that has the transactionID field set, then it MUST set the
transactionID field of the response to the same value. If a server
receives such request with a missing transactionID field, then it
MUST populate the transactionID field of the response with a server-
generated ID. Subsequent requests and responses MUST all set the
transactionID field to the thus established value. In all cases
where a transactionID is being used, a given client MUST NOT have
more than one transaction with the same transactionID in progress at
any time (to a given server). Servers are free to require uniqueness
of the transactionID or not, as long as they are able to correctly
associate messages with the corresponding transaction. Typically,
this means that a server will require the {client, transactionID}
tuple to be unique, or even the transactionID alone to be unique, if
it cannot distinguish clients based on transport-level information.
A server receiving the first message of a transaction (which requires
more than a single request/response pair) that contains a
transactionID that does not allow it to meet the above constraints
(typically because the transactionID is already in use) MUST send
back an ErrorMsgContent with a PKIFailureInfo of transactionIdInUse.
It is RECOMMENDED that the clients fill the transactionID field with
128 bits of (pseudo-) random data for the start of a transaction to
reduce the probability of having the transactionID in use at the
server.
The senderNonce and recipNonce fields protect the PKIMessage against
replay attacks. The senderNonce will typically be 128 bits of
(pseudo-) random data generated by the sender, whereas the recipNonce
is copied from the senderNonce of the previous message in the
transaction.
The messageTime field contains the time at which the sender created
the message. This may be useful to allow end entities to correct/
check their local time for consistency with the time on a central
system.
The freeText field may be used to send a human-readable message to
the recipient (in any number of languages). The first language used
in this sequence indicates the desired language for replies.
The generalInfo field may be used to send machine-processable
additional data to the recipient. The following generalInfo
extensions are defined and MAY be supported.
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5.1.1.1. ImplicitConfirm
This is used by the EE to inform the CA that it does not wish to send
a certificate confirmation for issued certificates.
id-it-implicitConfirm OBJECT IDENTIFIER ::= {id-it 13}
ImplicitConfirmValue ::= NULL
If the CA grants the request to the EE, it MUST put the same
extension in the PKIHeader of the response. If the EE does not find
the extension in the response, it MUST send the certificate
confirmation.
5.1.1.2. ConfirmWaitTime
This is used by the CA to inform the EE how long it intends to wait
for the certificate confirmation before revoking the certificate and
deleting the transaction.
id-it-confirmWaitTime OBJECT IDENTIFIER ::= {id-it 14}
ConfirmWaitTimeValue ::= GeneralizedTime
5.1.1.3. OrigPKIMessage
An RA MAY include the original PKIMessage from the EE in the
generalInfo field of the PKIHeader of a PKIMessage. This is used by
the RA to inform the CA of the original PKIMessage that it received
from the EE and modified in some way (e.g., added or modified
particular field values or added new extensions) before forwarding
the new PKIMessage. This accommodates, for example, cases in which
the CA wishes to check POP or other information on the original EE
message.
Note: If the changes made by the RA to the original PKIMessage break
the POP of a certificate request, the RA can set the popo field to
raVerified, see Section 5.2.8.4.
Although the infoValue is PKIMessages, it MUST contain exactly one
PKIMessage.
id-it-origPKIMessage OBJECT IDENTIFIER ::= {id-it 15}
OrigPKIMessageValue ::= PKIMessages
5.1.1.4. CertProfile
This is used by the EE to indicate specific certificate profiles,
e.g., when requesting a new certificate or a certificate request
template; see Section 5.3.19.16.
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id-it-certProfile OBJECT IDENTIFIER ::= {id-it 21}
CertProfileValue ::= SEQUENCE SIZE (1..MAX) OF UTF8String
When used in a p10cr message, the CertProfileValue sequence MUST NOT
contain multiple certificate profile names. When used in an
ir/cr/kur/genm message, the CertProfileValue sequence MUST NOT
contain more certificate profile names than the number of CertReqMsg
or GenMsgContent InfoTypeAndValue elements contained in the message
body.
The certificate profile names in the CertProfileValue sequence relate
to the CertReqMsg or GenMsgContent InfoTypeAndValue elements in the
given order. An empty string means no certificate profile name is
associated with the respective CertReqMsg or GenMsgContent
InfoTypeAndValue element. If the CertProfileValue sequence contains
less certificate profile entries than CertReqMsg or GenMsgContent
InfoTypeAndValue elements, the remaining CertReqMsg or GenMsgContent
InfoTypeAndValue elements have no profile name associated with them.
5.1.1.5. KemCiphertextInfo
A PKI entity MAY provide the KEM ciphertext for MAC-based message
protection using KEM (see Section 5.1.3.4) in the generalInfo field
of a request message to a PKI management entity if it knows that the
PKI management entity uses a KEM key pair and has its public key.
id-it-KemCiphertextInfo OBJECT IDENTIFIER ::= { id-it TBD1 }
KemCiphertextInfoValue ::= KemCiphertextInfo
For more details of KEM-based message protection see Section 5.1.3.4.
See Section 5.3.19.18 for the definition of {id-it TBD1}.
5.1.2. PKI Message Body
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PKIBody ::= CHOICE {
ir [0] CertReqMessages, --Initialization Req
ip [1] CertRepMessage, --Initialization Resp
cr [2] CertReqMessages, --Certification Req
cp [3] CertRepMessage, --Certification Resp
p10cr [4] CertificationRequest, --PKCS #10 Cert. Req.
popdecc [5] POPODecKeyChallContent --pop Challenge
popdecr [6] POPODecKeyRespContent, --pop Response
kur [7] CertReqMessages, --Key Update Request
kup [8] CertRepMessage, --Key Update Response
krr [9] CertReqMessages, --Key Recovery Req
krp [10] KeyRecRepContent, --Key Recovery Resp
rr [11] RevReqContent, --Revocation Request
rp [12] RevRepContent, --Revocation Response
ccr [13] CertReqMessages, --Cross-Cert. Request
ccp [14] CertRepMessage, --Cross-Cert. Resp
ckuann [15] CAKeyUpdAnnContent, --CA Key Update Ann.
cann [16] CertAnnContent, --Certificate Ann.
rann [17] RevAnnContent, --Revocation Ann.
crlann [18] CRLAnnContent, --CRL Announcement
pkiconf [19] PKIConfirmContent, --Confirmation
nested [20] NestedMessageContent, --Nested Message
genm [21] GenMsgContent, --General Message
genp [22] GenRepContent, --General Response
error [23] ErrorMsgContent, --Error Message
certConf [24] CertConfirmContent, --Certificate Confirm
pollReq [25] PollReqContent, --Polling Request
pollRep [26] PollRepContent --Polling Response
}
The specific types are described in Section 5.3 below.
5.1.3. PKI Message Protection
Some PKI messages will be protected for integrity.
Note: If an asymmetric algorithm is used to protect a message and the
relevant public component has been certified already, then the origin
of the message can also be authenticated. On the other hand, if the
public component is uncertified, then the message origin cannot be
automatically authenticated, but may be authenticated via out-of-band
means.
When protection is applied, the following structure is used:
PKIProtection ::= BIT STRING
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The input to the calculation of PKIProtection is the DER encoding of
the following data structure:
ProtectedPart ::= SEQUENCE {
header PKIHeader,
body PKIBody
}
There MAY be cases in which the PKIProtection BIT STRING is
deliberately not used to protect a message (i.e., this OPTIONAL field
is omitted) because other protection, external to PKIX, will be
applied instead. Such a choice is explicitly allowed in this
specification. Examples of such external protection include CMS
[RFC5652] and Security Multiparts [RFC1847] encapsulation of the
PKIMessage (or simply the PKIBody (omitting the CHOICE tag), if the
relevant PKIHeader information is securely carried in the external
mechanism). It is noted, however, that many such external mechanisms
require that the end entity already possesses a public-key
certificate, and/or a unique Distinguished Name, and/or other such
infrastructure-related information. Thus, they may not be
appropriate for initial registration, key-recovery, or any other
process with "boot-strapping" characteristics. For those cases it
may be necessary that the PKIProtection parameter be used. In the
future, if/when external mechanisms are modified to accommodate boot-
strapping scenarios, the use of PKIProtection may become rare or non-
existent.
Depending on the circumstances, the PKIProtection bits may contain a
Message Authentication Code (MAC) or signature. Only the following
cases can occur:
5.1.3.1. Shared Secret Information
In this case, the sender and recipient share secret information with
sufficient entropy (established via out-of-band means).
PKIProtection will contain a MAC value and the protectionAlg MAY be
one of the options described in CMP Algorithms Section 6.1 [RFC9481].
The algorithm identifier id-PasswordBasedMac is defined in
Section 4.4 of [RFC4211] and updated by [RFC9045]. It is mentioned
in Section 6.1.1 of [RFC9481] for backward compatibility. More
modern alternatives are listed in Section 6.1 of [RFC9481].
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id-PasswordBasedMac OBJECT IDENTIFIER ::= {1 2 840 113533 7 66 13}
PBMParameter ::= SEQUENCE {
salt OCTET STRING,
owf AlgorithmIdentifier,
iterationCount INTEGER,
mac AlgorithmIdentifier
}
The following text gives a method of key expansion to be used when
the MAC-algorithm requires an input length that is larger than the
size of the one-way-function.
Note: Section 4.4 of [RFC4211] and [RFC9045] do not mention this key
expansion method and gives an example using HMAC algorithms where key
expansion is not needed. It is recognized that this omission in
[RFC4211] can lead to confusion and possible incompatibility if
[RFC4210] key expansion is not used when needed. Therefore, when key
expansion is required (when K > H) the key expansion defined in in
the following text MUST be used.
In the above protectionAlg, the salt value is appended to the shared
secret input. The OWF is then applied iterationCount times, where
the salted secret is the input to the first iteration and, for each
successive iteration, the input is set to be the output of the
previous iteration. The output of the final iteration (called
"BASEKEY" for ease of reference, with a size of "H") is what is used
to form the symmetric key. If the MAC algorithm requires a K-bit key
and K <= H, then the most significant K bits of BASEKEY are used. If
K > H, then all of BASEKEY is used for the most significant H bits of
the key, OWF("1" || BASEKEY) is used for the next most significant H
bits of the key, OWF("2" || BASEKEY) is used for the next most
significant H bits of the key, and so on, until all K bits have been
derived. [Here "N" is the ASCII byte encoding the number N and "||"
represents concatenation.]
Note: It is RECOMMENDED that the fields of PBMParameter remain
constant throughout the messages of a single transaction (e.g.,
ir/ip/certConf/pkiConf) to reduce the overhead associated with
PasswordBasedMac computation.
5.1.3.2. DH Key Pairs
Where the sender and receiver possess finite-field or elliptic-curve-
based Diffie-Hellman certificates with compatible DH parameters, in
order to protect the message the end entity must generate a symmetric
key based on its private DH key value and the DH public key of the
recipient of the PKI message. PKIProtection will contain a MAC value
keyed with this derived symmetric key and the protectionAlg will be
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the following:
id-DHBasedMac OBJECT IDENTIFIER ::= {1 2 840 113533 7 66 30}
DHBMParameter ::= SEQUENCE {
owf AlgorithmIdentifier,
-- AlgId for a One-Way Function
mac AlgorithmIdentifier
-- the MAC AlgId
}
In the above protectionAlg, OWF is applied to the result of the
Diffie-Hellman computation. The OWF output (called "BASEKEY" for
ease of reference, with a size of "H") is what is used to form the
symmetric key. If the MAC algorithm requires a K-bit key and K <= H,
then the most significant K bits of BASEKEY are used. If K > H, then
all of BASEKEY is used for the most significant H bits of the key,
OWF("1" || BASEKEY) is used for the next most significant H bits of
the key, OWF("2" || BASEKEY) is used for the next most significant H
bits of the key, and so on, until all K bits have been derived.
[Here "N" is the ASCII byte encoding the number N and "||" represents
concatenation.]
Note: Hash algorithms that can be used as one-way functions are
listed in CMP Algorithms [RFC9481] Section 2.
5.1.3.3. Signature
In this case, the sender possesses a signature key pair and simply
signs the PKI message. PKIProtection will contain the signature
value and the protectionAlg will be an AlgorithmIdentifier for a
digital signature MAY be one of the options described in CMP
Algorithms Section 3 [RFC9481].
5.1.3.4. Key Encapsulation
In case the sender of a message has a Key Encapsulation Mechanism
(KEM) key pair, it can be used to establish a shared secret key for
MAC-based message protection. This can be used for message
authentication.
This approach uses the definition of Key Encapsulation Mechanism
(KEM) algorithm functions in [I-D.ietf-lamps-cms-kemri], Section 1
which is copied here for completeness.
A KEM algorithm provides three functions:
* KeyGen() -> (pk, sk):
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Generate the public key (pk) and a private (secret) key (sk).
* Encapsulate(pk) -> (ct, ss):
Given the recipient's public key (pk), produce a ciphertext (ct)
to be passed to the recipient and shared secret (ss) for the
originator.
* Decapsulate(sk, ct) -> ss:
Given the private key (sk) and the ciphertext (ct), produce the
shared secret (ss) for the recipient.
To support a particular KEM algorithm, the CMP originator MUST
support the KEM Encapsulate() function. To support a particular KEM
algorithm, the CMP recipient MUST support the KEM KeyGen() function
and the KEM Decapsulate() function. The recipient's public key is
usually carried in a certificate [RFC5280].
Note: In this section both entities in the communication need to send
and receive messages. Either side of the communication may
independently wish to protect messages using a MAC key derived from
the KEM output. For ease of explanation we use the term "Alice" to
denote the entity possessing the KEM key pair and who wishes to
provide MAC-based message protection, and "Bob" to denote the entity
who needs to verify it.
Assuming Bob possesses Alice's KEM public key, he generates the
ciphertext using KEM encapsulation and transfers it to Alice in an
InfoTypeAndValue structure. Alice then retrieves the KEM shared
secret from the ciphertext using KEM decapsulation and the associated
KEM private key. Using a key derivation function (KDF), she derives
a shared secret key from the KEM shared secret and other data sent by
Bob. PKIProtection will contain a MAC value calculated using that
shared secret key, and the protectionAlg will be the following:
id-KemBasedMac OBJECT IDENTIFIER ::= {1 2 840 113533 7 66 16}
KemBMParameter ::= SEQUENCE {
kdf AlgorithmIdentifier{KEY-DERIVATION, {...}},
kemContext [0] OCTET STRING OPTIONAL,
len INTEGER (1..MAX),
mac AlgorithmIdentifier{MAC-ALGORITHM, {...}}
}
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Note: The OID for id-KemBasedMac was assigned on the private-use arc
{ iso(1) member-body(2) us(840) nortelnetworks(113533) entrust(7) },
and not assigned on an IANA-owned arc because the authors wished to
placed it on the same branch as the existing OIDs for id-
PasswordBasedMac and id-DHBasedMac.
kdf is the algorithm identifier of the chosen KDF, and any associated
parameters, used to derive the shared secret key.
kemContext MAY be used to transfer additional algorithm specific
context information, see also the definition of ukm in
[I-D.ietf-lamps-cms-kemri], Section 3.
len is the output length of the KDF and MUST be the desired size of
the key to be used for MAC-based message protection.
mac is the algorithm identifier of the chosen MAC algorithm, and any
associated parameters, used to calculate the MAC value.
The KDF and MAC algorithms MAY be chosen from the options in CMP
Algorithms [RFC9481].
The InfoTypeAndValue transferring the KEM ciphertext uses OID id-it-
KemCiphertextInfo. It contains a KemCiphertextInfo structure as
defined in Section 5.3.19.18.
Note: This InfoTypeAndValue can be carried in a genm/genp message
body as specified in Section 5.3.19.18 or in the generalInfo field of
PKIHeader in messages of other types, see Section 5.1.1.5.
In the following, a generic message flow for MAC-based protection
using KEM is specified in more detail. It is assumed that Bob
possesses the public KEM key of Alice. Alice can be the initiator of
a PKI management operation or the responder. For more detailed
figures see Appendix E.
Generic Message Flow:
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Step# Alice Bob
1 perform KEM Encapsulate
<- KEM Ciphertext <-
2 perform KEM Decapsulate
perform key derivation
format message with
MAC-based protection
-> message ->
3 perform key derivation
verify MAC-based
protection
------------------- Alice authenticated by Bob --------------------
Figure 2: Generic Message Flow when Alice has a KEM key pair
1. Bob needs to possess the authentic public KEM key pk of Alice,
for instance contained in a KEM certificate that was received and
successfully validated by Bob beforehand.
Bob generates a shared secret ss and the associated ciphertext ct
using the KEM Encapsulate function with Alice's public KEM key
pk. Bob MUST NOT reuse the ss and ct for other PKI management
operations. From this data, Bob produces a KemCiphertextInfo
structure including the KEM algorithm identifier and the
ciphertext ct and sends it to Alice in an InfoTypeAndValue
structure as defined in Section 5.3.19.18.
Encapsulate(pk) -> (ct, ss)
2. Alice decapsulates the shared secret ss from the ciphertext ct
using the KEM Decapsulate function and its private KEM key sk.
Decapsulate(ct, sk) -> (ss)
If the decapsulation operation outputs an error, any failInfo
field in an error response message SHALL contain the value
badMessageCheck and the PKI management operation SHALL be
terminated.
Alice derives the shared secret key ssk using a KDF. The shared
secret ss is used as input key material for the KDF, the value
len is the desired output length of the KDF as required by the
MAC algorithm to be used for message protection. KDF, len, and
MAC will be transferred to Bob in the protectionAlg
KemBMParameter. The DER-encoded KemOtherInfo structure, as
defined below, is used as context for the KDF.
KDF(ss, len, context)->(ssk)
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The shared secret key ssk is used for MAC-based protection by
Alice.
3. Bob derives the same shared secret key ssk using the KDF. Also
here the shared secret ss is used as input key material for the
KDF, the value len is the desired output length for the KDF, and
the DER-encoded KemOtherInfo structure constructed in the same
way as on Alice's side is used as context for the KDF.
KDF(ss, len, context)->(ssk)
Bob uses the shared secret key ssk for verifying the MAC-based
protection of the message received and in this way authenticates
Alice.
This shared secret key ssk can be reused by Alice for MAC-based
protection of further messages sent to Bob within the current PKI
management operation.
This approach employs the notation of KDF(IKM, L, info) as described
in [I-D.ietf-lamps-cms-kemri], Section 5 with the following changes:
* IKM is the input key material. It is the symmetric secret called
ss resulting from the key encapsulation mechanism.¶
* L is dependent of the MAC algorithm that is used with the shared
secret key for CMP message protection and is called len in this
document
* info is an additional input to the KDF, is called context in this
document, and contains the DER-encoded KemOtherInfo structure
defined as:
KemOtherInfo ::= SEQUENCE {
staticString PKIFreeText,
transactionID OCTET STRING,
kemContext [0] OCTET STRING OPTIONAL
}
staticString MUST be "CMP-KEM".
transactionID MUST be the value from the message containing the
ciphertext ct in KemCiphertextInfo.
Note: The transactionID is used to ensure domain separation of the
derived shared secret key between different PKI management
operations. For all PKI management operations with more than one
exchange the transactionID MUST be set anyway, see Section 5.1.1.
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In case Bob provided a infoValue of type KemCiphertextInfo to
Alice in the initial request message, see Figure 4 of Appendix E,
the transactionID MUST be set by Bob.
kemContext MAY contain additional algorithm specific context
information.
* OKM is the output keying material of the KDF used for MAC-based
message protection of length len and is called ssk in this
document.
There are various ways how Alice can request, and Bob can provide the
KEM ciphertext, see Appendix E for details. The KemCiphertextInfo
can be requested using PKI general messages as described in
Section 5.3.19.18. Alternatively, the generalInfo field of the
PKIHeader can be used to convey the same request and response
InfoTypeAndValue structures as described in Section 5.1.1.5. The
procedure works also without Alice explicitly requesting the KEM
ciphertext in case Bob knows a KEM key of Alice beforehand and can
expect that she is ready to use it.
If both the initiator and responder in a PKI management operation
have KEM key pairs, this procedure can be applied by both entities
independently, establishing and using different shared secret keys
for either direction.
5.1.3.5. Multiple Protection
When receiving a protected PKI message, a PKI management entity, such
as an RA, MAY forward that message adding its own protection (which
is a MAC or a signature, depending on the information and
certificates shared between the RA and the CA). Additionally,
multiple PKI messages MAY be aggregated. There are several use cases
for such messages.
* The RA confirms having validated and authorized a message and
forwards the original message unchanged.
* A PKI management entity collects several messages that are to be
forwarded in the same direction and forwards them in a batch.
Request messages can be transferred as batch upstream (towards the
CA); response or announce messages can be transferred as batch
downstream (towards an RA but not to the EE). For instance, this
can be used when bridging an off-line connection between two PKI
management entities.
These use cases are accomplished by nesting the messages within a new
PKI message. The structure used is as follows:
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NestedMessageContent ::= PKIMessages
In case an RA needs to modify a request message, it MAY include the
original PKIMessage in the generalInfo field of the modified message
as described in Section 5.1.1.3.
5.2. Common Data Structures
Before specifying the specific types that may be placed in a PKIBody,
we define some data structures that are used in more than one case.
5.2.1. Requested Certificate Contents
Various PKI management messages require that the originator of the
message indicate some of the fields that are required to be present
in a certificate. The CertTemplate structure allows an end entity or
RA to specify as much as it wishes about the certificate it requires.
CertTemplate is identical to a Certificate, but with all fields
optional.
Note: Even if the originator completely specifies the contents of a
certificate it requires, a CA is free to modify fields within the
certificate actually issued. If the modified certificate is
unacceptable to the requester, the requester MUST send back a
certConf message that either does not include this certificate (via a
CertHash), or does include this certificate (via a CertHash) along
with a status of "rejected". See Section 5.3.18 for the definition
and use of CertHash and the certConf message.
Note: Before requesting a new certificate, an end entity can request
a certTemplate structure as a kind of certificate request blueprint,
in order to learn which data the CA expects to be present in the
certificate request, see Section 5.3.19.16.
See CRMF [RFC4211] for CertTemplate syntax.
If certTemplate is an empty SEQUENCE (i.e., all fields omitted), then
the controls field in the CertRequest structure MAY contain the id-
regCtrl-altCertTemplate control, specifying a template for a
certificate other than an X.509v3 public-key certificate.
Conversely, if certTemplate is not empty (i.e., at least one field is
present), then controls MUST NOT contain id-regCtrl-altCertTemplate.
The new control is defined as follows:
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id-regCtrl-altCertTemplate OBJECT IDENTIFIER ::= { iso(1)
identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) pkip(5) regCtrl(1) 7}
AltCertTemplate ::= AttributeTypeAndValue
See also [RFC4212] for more details on how to manage certificates in
alternative formats using CRMF [RFC4211] syntax.
5.2.2. Encrypted Values
Where encrypted data (in this specification, private keys,
certificates, or revocation passphrase) is sent in PKI messages, the
EncryptedKey data structure is used.
EncryptedKey ::= CHOICE {
encryptedValue EncryptedValue, -- deprecated
envelopedData [0] EnvelopedData }
See Certificate Request Message Format (CRMF) [RFC4211] for
EncryptedKey and EncryptedValue syntax and Cryptographic Message
Syntax (CMS) [RFC5652] for EnvelopedData syntax. Using the
EncryptedKey data structure offers the choice to either use
EncryptedValue (for backward compatibility only) or EnvelopedData.
The use of the EncryptedValue structure has been deprecated in favor
of the EnvelopedData structure. Therefore, it is RECOMMENDED to use
EnvelopedData.
Note: The EncryptedKey structure defined in CRMF [RFC4211] is used
here, which makes the update backward compatible. Using the new
syntax with the untagged default choice EncryptedValue is bits-on-
the-wire compatible with the old syntax.
To indicate support for EnvelopedData, the pvno cmp2021 has been
introduced. Details on the usage of the protocol version number
(pvno) are described in Section 7.
The EncryptedKey data structure is used in CMP to transport a private
key, certificate, or revocation passphrase in encrypted form.
EnvelopedData is used as follows:
* It contains only one RecipientInfo structure because the content
is encrypted only for one recipient.
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* It may contain a private key in the AsymmetricKeyPackage
structure, as defined in [RFC5958], that is wrapped in a
SignedData structure, as specified in Section 5 of [RFC5652] and
[RFC8933], signed by the Key Generation Authority.
* It may contain a certificate or revocation passphrase directly in
the encryptedContent field.
The content of the EnvelopedData structure, as specified in Section 6
of [RFC5652], MUST be encrypted using a newly generated symmetric
content-encryption key. This content-encryption key MUST be securely
provided to the recipient using one of three key management
techniques.
The choice of the key management technique to be used by the sender
depends on the credential available at the recipient:
* recipient's certificate with an algorithm identifier and a public
key that supports key transport and where any given key usage
extension allows keyEncipherment: The content-encryption key will
be protected using the key transport key management technique, as
specified in Section 6.2.1 of [RFC5652].
* recipient's certificate with an algorithm identifier and a public
key that supports key agreement and where any given key usage
extension allows keyAgreement: The content-encryption key will be
protected using the key agreement key management technique, as
specified in Section 6.2.2 of [RFC5652].
* a password or shared secret: The content-encryption key will be
protected using the password-based key management technique, as
specified in Section 6.2.4 of [RFC5652].
* recipient's certificate with an algorithm identifier and a public
key that supports key encapsulation mechanism and where any given
key usage extension allows keyEncipherment: The content-encryption
key will be protected using the key management technique for KEM
keys, as specified in [I-D.ietf-lamps-cms-kemri].
Note: There are cases where the algorithm identifier, the type of the
public key, and the key usage extension will not be sufficient to
decide on the key management technique to use, e.g., when
rsaEncryption is the algorithm identifier. In such cases it is a
matter of local policy to decide.
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5.2.3. Status codes and Failure Information for PKI Messages
All response messages will include some status information. The
following values are defined.
PKIStatus ::= INTEGER {
accepted (0),
grantedWithMods (1),
rejection (2),
waiting (3),
revocationWarning (4),
revocationNotification (5),
keyUpdateWarning (6)
}
Responders may use the following syntax to provide more information
about failure cases.
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PKIFailureInfo ::= BIT STRING {
badAlg (0),
badMessageCheck (1),
badRequest (2),
badTime (3),
badCertId (4),
badDataFormat (5),
wrongAuthority (6),
incorrectData (7),
missingTimeStamp (8),
badPOP (9),
certRevoked (10),
certConfirmed (11),
wrongIntegrity (12),
badRecipientNonce (13),
timeNotAvailable (14),
unacceptedPolicy (15),
unacceptedExtension (16),
addInfoNotAvailable (17),
badSenderNonce (18),
badCertTemplate (19),
signerNotTrusted (20),
transactionIdInUse (21),
unsupportedVersion (22),
notAuthorized (23),
systemUnavail (24),
systemFailure (25),
duplicateCertReq (26)
}
PKIStatusInfo ::= SEQUENCE {
status PKIStatus,
statusString PKIFreeText OPTIONAL,
failInfo PKIFailureInfo OPTIONAL
}
5.2.4. Certificate Identification
In order to identify particular certificates, the CertId data
structure is used.
See [RFC4211] for CertId syntax.
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5.2.5. Out-of-band root CA Public Key
Each root CA must be able to publish its current public key via some
"out-of-band" means. While such mechanisms are beyond the scope of
this document, we define data structures that can support such
mechanisms.
There are generally two methods available: either the CA directly
publishes its self-signed certificate, or this information is
available via the Directory (or equivalent) and the CA publishes a
hash of this value to allow verification of its integrity before use.
OOBCert ::= Certificate
The fields within this certificate are restricted as follows:
* The certificate MUST be self-signed (i.e., the signature must be
verifiable using the SubjectPublicKeyInfo field);
* The subject and issuer fields MUST be identical;
* If the subject field is NULL, then both subjectAltNames and
issuerAltNames extensions MUST be present and have exactly the
same value;
* The values of all other extensions must be suitable for a self-
signed certificate (e.g., key identifiers for subject and issuer
must be the same).
OOBCertHash ::= SEQUENCE {
hashAlg [0] AlgorithmIdentifier OPTIONAL,
certId [1] CertId OPTIONAL,
hashVal BIT STRING
}
The intention of the hash value is that anyone who has securely
received the hash value (via the out-of-band means) can verify a
self-signed certificate for that CA.
5.2.6. Archive Options
Requesters may indicate that they wish the PKI to archive a private
key value using the PKIArchiveOptions structure.
See [RFC4211] for PKIArchiveOptions syntax.
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5.2.7. Publication Information
Requesters may indicate that they wish the PKI to publish a
certificate using the PKIPublicationInfo structure.
See [RFC4211] for PKIPublicationInfo syntax.
5.2.8. Proof-of-Possession Structures
The proof-of-possession structure used is indicated in the popo field
of type ProofOfPossession in the CertReqMsg sequence, see Section 4
of [RFC4211].
ProofOfPossession ::= CHOICE {
raVerified [0] NULL,
signature [1] POPOSigningKey,
keyEncipherment [2] POPOPrivKey,
keyAgreement [3] POPOPrivKey
}
5.2.8.1. raVerified
An EE MUST NOT use raVerified. If an RA performs changes to a
certification request breaking the provided proof-of-possession
(POP), or if the RA requests a certificate on behalf of an EE and
cannot provide the POP itself, the RA MUST use raVerified.
Otherwise, it SHOULD NOT use raVerified.
When introducing raVerified, the RA MUST check the existing POP, or
it MUST ensure by other means that the EE is the holder of the
private key. The RA MAY provide the original message containing the
POP in the generalInfo field using the id-it-origPKIMessage, see
Section 5.1.1.3, enabling the CA to verify it.
5.2.8.2. POPOSigningKey Structure
If the certification request is for a key pair that supports signing
(i.e., a request for a verification certificate), then the proof-of-
possession of the private key is demonstrated through use of the
POPOSigningKey structure, for details see Section 4.1 of [RFC4211].
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POPOSigningKey ::= SEQUENCE {
poposkInput [0] POPOSigningKeyInput OPTIONAL,
algorithmIdentifier AlgorithmIdentifier,
signature BIT STRING
}
POPOSigningKeyInput ::= SEQUENCE {
authInfo CHOICE {
sender [0] GeneralName,
publicKeyMAC PKMACValue
},
publicKey SubjectPublicKeyInfo
}
PKMACValue ::= SEQUENCE {
algId AlgorithmIdentifier,
value BIT STRING
}
Note: For the purposes of this specification, the ASN.1 comment given
in Appendix C of [RFC4211] pertains not only to certTemplate, but
also to the altCertTemplate control as defined in Section 5.2.1.
If certTemplate (or the altCertTemplate control) contains the subject
and publicKey values, then poposkInput MUST be omitted and the
signature MUST be computed on the DER-encoded value of certReq field
of the CertReqMsg (or the DER-encoded value of AltCertTemplate). If
certTemplate/altCertTemplate does not contain both the subject and
public key values (i.e., if it contains only one of these, or
neither), then poposkInput MUST be present and the signature MUST be
computed on the DER-encoded value of poposkInput (i.e., the "value"
OCTETs of the POPOSigningKeyInput DER).
In the special case that the CA/RA has a DH certificate that is known
to the EE and the certification request is for a key agreement key
pair, the EE can also use the POPOSigningKey structure (where the
algorithmIdentifier field is DHBasedMAC and the signature field is
the MAC) for demonstrating POP.
5.2.8.3. POPOPrivKey Structure
If the certification request is for a key pair that does not support
signing (i.e., a request for an encryption or key agreement
certificate), then the proof-of-possession of the private key is
demonstrated through use of the POPOPrivKey structure in one of
following three ways, for details see Section 4.2 and 4.3 of
[RFC4211].
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POPOPrivKey ::= CHOICE {
thisMessage [0] BIT STRING, -- deprecated
subsequentMessage [1] SubsequentMessage,
dhMAC [2] BIT STRING, -- deprecated
agreeMAC [3] PKMACValue,
encryptedKey [4] EnvelopedData
}
SubsequentMessage ::= INTEGER {
encrCert (0),
challengeResp (1)
}
5.2.8.3.1. Inclusion of the Private Key
This method demonstrates proof-of-possession of the private key by
including the encrypted private key in the CertRequest in the
POPOPrivKey structure or in the PKIArchiveOptions control structure,
depending upon whether or not archival of the private key is also
desired.
For a certification request message indicating cmp2021(3) in the pvno
field of the PKIHeader, the encrypted private key MUST be transferred
in the encryptedKey choice of POPOPrivKey (or within the
PKIArchiveOptions control) in a CMS EnvelopedData structure as
defined in Section 5.2.2.
Note: The thisMessage choice has been deprecated in favor of
encryptedKey. When using cmp2000(2) in the certification request
message header for backward compatibility, the thisMessage choice of
POPOPrivKey is used containing the encrypted private key in an
EncryptedValue structure wrapped in a BIT STRING. This allows the
necessary conveyance and protection of the private key while
maintaining bits-on-the-wire compatibility with [RFC4211].
5.2.8.3.2. Indirect Method - Encrypted Certificate
The "indirect" method mentioned previously in Section 4.3
demonstrates proof-of-possession of the private key by having the CA
return the requested certificate in encrypted form, see
Section 5.2.2. This method is indicated in the CertRequest by
requesting the encrCert option in the subsequentMessage choice of
POPOPrivKey.
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EE RA/CA
---- req ---->
<--- rep (enc cert) -----
---- conf (cert hash) ---->
<--- ack -----
The end entity proves knowledge of the private key to the CA by
providing the correct CertHash for this certificate in the certConf
message. This demonstrates POP because the EE can only compute the
correct CertHash if it is able to recover the encrypted certificate,
and it can only recover the certificate if it is able to obtain the
symmetric key using the required private key. Clearly, for this to
work, the CA MUST NOT publish the certificate until the certConf
message arrives (when certHash is to be used to demonstrate POP).
See Section 5.3.18 for further details and see Section 8.11 for
security considerations regarding use of Certificate Transparency
logs.
5.2.8.3.3. Direct Method - Challenge-Response Protocol
The "direct" method mentioned previously in Section 4.3 demonstrates
proof-of-possession of the private key by having the end entity
engage in a challenge-response protocol (using the messages popdecc
of type POPODecKeyChall and popdecr of type POPODecKeyResp; see
below) between CertReqMessages and CertRepMessage. This method is
indicated in the CertRequest by requesting the challengeResp option
in the subsequentMessage choice of POPOPrivKey.
Note: This method would typically be used in an environment in which
an RA verifies POP and then makes a certification request to the CA
on behalf of the end entity. In such a scenario, the CA trusts the
RA to have done POP correctly before the RA requests a certificate
for the end entity.
The complete protocol then looks as follows (note that req' does not
necessarily encapsulate req as a nested message):
EE RA CA
---- req ---->
<--- chall ---
---- resp --->
---- req' --->
<--- rep -----
---- conf --->
<--- ack -----
<--- rep -----
---- conf --->
<--- ack -----
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This protocol is obviously much longer than the exchange given in
Section 5.2.8.3.2 above, but allows a local Registration Authority to
be involved and has the property that the certificate itself is not
actually created until the proof-of-possession is complete. In some
environments, a different order of the above messages may be
required, such as the following (this may be determined by policy):
EE RA CA
---- req ---->
<--- chall ---
---- resp --->
---- req' --->
<--- rep -----
<--- rep -----
---- conf --->
---- conf --->
<--- ack -----
<--- ack -----
The challenge-response messages for proof-of-possession of a private
key are specified as follows (for decryption keys see [MvOV97], p.404
for details). This challenge-response exchange is associated with
the preceding certification request message (and subsequent
certification response and confirmation messages) by the
transactionID used in the PKIHeader and by the protection applied to
the PKIMessage.
POPODecKeyChallContent ::= SEQUENCE OF Challenge
Challenge ::= SEQUENCE {
owf AlgorithmIdentifier OPTIONAL,
witness OCTET STRING,
challenge OCTET STRING, -- deprecated
encryptedRand [0] EnvelopedData OPTIONAL
}
Rand ::= SEQUENCE {
int INTEGER,
sender GeneralName
}
More details on the fields in this syntax is available in Appendix F.
For a popdecc message indicating cmp2021(3) in the pvno field of the
PKIHeader, the encryption of Rand MUST be transferred in the
encryptedRand field in a CMS EnvelopedData structure as defined in
Section 5.2.2. The challenge field MUST contain an empty OCTET
STRING.
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Note: The challenge field has been deprecated in favor of
encryptedRand. When using cmp2000(2) in the popdecc message header
for backward compatibility, the challenge field MUST contain the
encryption (involving the public key for which the certification
request is being made) of Rand and encryptedRand MUST be omitted.
Using challenge (omitting the optional encryptedRand field) is bit-
compatible with [RFC4210]. Note that the size of Rand, when used
with challenge, needs to be appropriate for encryption, involving the
public key of the requester. If, in some environment, names are so
long that they cannot fit (e.g., very long DNs), then whatever
portion will fit should be used (as long as it includes at least the
common name, and as long as the receiver is able to deal meaningfully
with the abbreviation).
POPODecKeyRespContent ::= SEQUENCE OF INTEGER
On receiving the popdecc message, the end entity decrypts all
included challenges and responds with a popdecr message containing
the decrypted integer values in the same order.
5.2.8.4. Summary of PoP Options
The text in this section provides several options with respect to POP
techniques. Using "SK" for "signing key", "EK" for "encryption key",
"KAK" for "key agreement key", and "KEMK" for "key encapsulation
mechanism key", the techniques may be summarized as follows:
RAVerified;
SKPOP;
EKPOPThisMessage; -- deprecated
KAKPOPThisMessage; -- deprecated
EKPOPEncryptedKey;
KAKPOPEncryptedKey;
KEMKPOPEncryptedKey;
KAKPOPThisMessageDHMAC;
EKPOPEncryptedCert;
KAKPOPEncryptedCert;
KEMKPOPEncryptedCert;
EKPOPChallengeResp;
KAKPOPChallengeResp; and
KEMKPOPChallengeResp.
Given this array of options, it is natural to ask how an end entity
can know what is supported by the CA/RA (i.e., which options it may
use when requesting certificates). The following guidelines should
clarify this situation for EE implementers.
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RAVerified: This is not an EE decision; the RA uses this if and only
if it has verified POP before forwarding the request on to the CA, so
it is not possible for the EE to choose this technique.
SKPOP: If the EE has a signing key pair, this is the only POP method
specified for use in the request for a corresponding certificate.
EKPOPThisMessage (deprecated), KAKPOPThisMessage (deprecated),
EKPOPEncryptedKey, KAKPOPEncryptedKey, KEMKPOPEncryptedKey: Whether
or not to give up its private key to the CA/RA is an EE decision. If
the EE decides to reveal its key, then these are the only POP methods
available in this specification to achieve this (and the key pair
type and protocol version used will determine which of these methods
to use). The reason for deprecating EKPOPThisMessage and
KAKPOPThisMessage options has been given in Section 5.2.8.3.1.
KAKPOPThisMessageDHMAC: The EE can only use this method if (1) the
CA/RA has a DH certificate available for this purpose, and (2) the EE
already has a copy of this certificate. If both these conditions
hold, then this technique is clearly supported and may be used by the
EE, if desired.
EKPOPEncryptedCert, KAKPOPEncryptedCert, KEMKPOPEncryptedCert,
EKPOPChallengeResp, KAKPOPChallengeResp, and KEMKPOPChallengeResp:
The EE picks one of these (in the subsequentMessage field) in the
request message, depending upon preference and key pair type. The EE
is not doing POP at this point; it is simply indicating which method
it wants to use. Therefore, if the CA/RA replies with a "badPOP"
error, the EE can re-request using the other POP method chosen in
subsequentMessage. Note, however, that this specification encourages
the use of the EncryptedCert choice and, furthermore, says that the
challenge-response would typically be used when an RA is involved and
doing POP verification. Thus, the EE should be able to make an
intelligent decision regarding which of these POP methods to choose
in the request message.
5.2.9. GeneralizedTime
GeneralizedTime is a standard ASN.1 type and SHALL be used as
specified in Section 4.1.2.5.2 of [RFC5280].
5.3. Operation-Specific Data Structures
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5.3.1. Initialization Request
An Initialization request message contains as the PKIBody a
CertReqMessages data structure, which specifies the requested
certificate(s). Typically, SubjectPublicKeyInfo, KeyId, and Validity
are the template fields which may be supplied for each certificate
requested (see the profiles defined in [RFC9483] Section 4.1.1,
Appendix C.4 and Appendix D.7 for further information). This message
is intended to be used for entities when first initializing into the
PKI.
See Section 5.2.1 and [RFC4211] for CertReqMessages syntax.
5.3.2. Initialization Response
An Initialization response message contains as the PKIBody an
CertRepMessage data structure, which has for each certificate
requested a PKIStatusInfo field, a subject certificate, and possibly
a private key (normally encrypted using EnvelopedData, see [RFC9483]
Section 4.1.6 for further information).
See Section 5.3.4 for CertRepMessage syntax. Note that if the PKI
Message Protection is "shared secret information" (see
Section 5.1.3), then any certificate transported in the caPubs field
may be directly trusted as a root CA certificate by the initiator.
5.3.3. Certification Request
A Certification request message contains as the PKIBody a
CertReqMessages data structure, which specifies the requested
certificates (see the profiles defined in [RFC9483] Section 4.1.2 and
Appendix C.2 for further information). This message is intended to
be used for existing PKI entities who wish to obtain additional
certificates.
See Section 5.2.1 and [RFC4211] for CertReqMessages syntax.
Alternatively, the PKIBody MAY be a CertificationRequest (this
structure is fully specified by the ASN.1 structure
CertificationRequest given in [RFC2986], see the profiles defined in
[RFC9483] Section 4.1.4 for further information). This structure may
be required for certificate requests for signing key pairs when
interoperation with legacy systems is desired, but its use is
strongly discouraged whenever not absolutely necessary.
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5.3.4. Certification Response
A Certification response message contains as the PKIBody a
CertRepMessage data structure, which has a status value for each
certificate requested, and optionally has a CA public key, failure
information, a subject certificate, and an encrypted private key.
CertRepMessage ::= SEQUENCE {
caPubs [1] SEQUENCE SIZE (1..MAX) OF CMPCertificate
OPTIONAL,
response SEQUENCE OF CertResponse
}
CertResponse ::= SEQUENCE {
certReqId INTEGER,
status PKIStatusInfo,
certifiedKeyPair CertifiedKeyPair OPTIONAL,
rspInfo OCTET STRING OPTIONAL
-- analogous to the id-regInfo-utf8Pairs string defined
-- for regInfo in CertReqMsg [RFC4211]
}
CertifiedKeyPair ::= SEQUENCE {
certOrEncCert CertOrEncCert,
privateKey [0] EncryptedKey OPTIONAL,
-- See [RFC4211] for comments on encoding.
publicationInfo [1] PKIPublicationInfo OPTIONAL
}
CertOrEncCert ::= CHOICE {
certificate [0] CMPCertificate,
encryptedCert [1] EncryptedKey
}
A p10cr message contains exactly one CertificationRequestInfo data
structure, as specified in PKCSNBS#10 [RFC2986], but no certReqId.
Therefore, the certReqId in the corresponding Certification Response
(cp) message MUST be set to -1.
Only one of the failInfo (in PKIStatusInfo) and certificate (in
CertifiedKeyPair) fields can be present in each CertResponse
(depending on the status). For some status values (e.g., waiting),
neither of the optional fields will be present.
Given an EncryptedCert and the relevant decryption key, the
certificate may be obtained. The purpose of this is to allow a CA to
return the value of a certificate, but with the constraint that only
the intended recipient can obtain the actual certificate. The
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benefit of this approach is that a CA may reply with a certificate
even in the absence of a proof that the requester is the end entity
that can use the relevant private key (note that the proof is not
obtained until the certConf message is received by the CA). Thus,
the CA will not have to revoke that certificate in the event that
something goes wrong with the proof-of-possession (but MAY do so
anyway, depending upon policy).
The use of EncryptedKey is described in Section 5.2.2.
Note: To indicate support for EnvelopedData, the pvno cmp2021 has
been introduced. Details on the usage of different protocol version
numbers (pvno) are described in Section 7.
5.3.5. Key Update Request Content
For key update requests the CertReqMessages syntax is used.
Typically, SubjectPublicKeyInfo, KeyId, and Validity are the template
fields that may be supplied for each key to be updated (see the
profiles defined in [RFC9483] Section 4.1.3 and Appendix C.6 for
further information). This message is intended to be used to request
updates to existing (non-revoked and non-expired) certificates
(therefore, it is sometimes referred to as a "Certificate Update"
operation). An update is a replacement certificate containing either
a new subject public key or the current subject public key (although
the latter practice may not be appropriate for some environments).
See Section 5.2.1 and [RFC4211] for CertReqMessages syntax.
5.3.6. Key Update Response Content
For key update responses, the CertRepMessage syntax is used. The
response is identical to the initialization response.
See Section 5.3.4 for CertRepMessage syntax.
5.3.7. Key Recovery Request Content
For key recovery requests the syntax used is identical to the
initialization request CertReqMessages. Typically,
SubjectPublicKeyInfo and KeyId are the template fields that may be
used to supply a signature public key for which a certificate is
required (see Appendix C profiles for further information).
See Section 5.2.1 and [RFC4211] for CertReqMessages syntax. Note
that if a key history is required, the requester must supply a
Protocol Encryption Key control in the request message.
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5.3.8. Key Recovery Response Content
For key recovery responses, the following syntax is used. For some
status values (e.g., waiting) none of the optional fields will be
present.
KeyRecRepContent ::= SEQUENCE {
status PKIStatusInfo,
newSigCert [0] Certificate OPTIONAL,
caCerts [1] SEQUENCE SIZE (1..MAX) OF
Certificate OPTIONAL,
keyPairHist [2] SEQUENCE SIZE (1..MAX) OF
CertifiedKeyPair OPTIONAL
}
5.3.9. Revocation Request Content
When requesting revocation of a certificate (or several
certificates), the following data structure is used (see the profiles
defined in [RFC9483] Section 4.2 for further information). The name
of the requester is present in the PKIHeader structure.
RevReqContent ::= SEQUENCE OF RevDetails
RevDetails ::= SEQUENCE {
certDetails CertTemplate,
crlEntryDetails Extensions OPTIONAL
}
5.3.10. Revocation Response Content
The revocation response is the response to the above message. If
produced, this is sent to the requester of the revocation. (A
separate revocation announcement message MAY be sent to the subject
of the certificate for which revocation was requested.)
RevRepContent ::= SEQUENCE {
status SEQUENCE SIZE (1..MAX) OF PKIStatusInfo,
revCerts [0] SEQUENCE SIZE (1..MAX) OF CertId OPTIONAL,
crls [1] SEQUENCE SIZE (1..MAX) OF CertificateList
OPTIONAL
}
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5.3.11. Cross Certification Request Content
Cross certification requests use the same syntax (CertReqMessages) as
normal certification requests, with the restriction that the key pair
MUST have been generated by the requesting CA and the private key
MUST NOT be sent to the responding CA (see the profiles defined in
Appendix D.6 for further information). This request MAY also be used
by subordinate CAs to get their certificates signed by the parent CA.
See Section 5.2.1 and [RFC4211] for CertReqMessages syntax.
5.3.12. Cross Certification Response Content
Cross certification responses use the same syntax (CertRepMessage) as
normal certification responses, with the restriction that no
encrypted private key can be sent.
See Section 5.3.4 for CertRepMessage syntax.
5.3.13. CA Key Update Announcement Content
When a CA updates its own key pair, the following data structure MAY
be used to announce this event.
CAKeyUpdAnnContent ::= SEQUENCE {
oldWithNew Certificate,
newWithOld Certificate,
newWithNew Certificate
}
5.3.14. Certificate Announcement
This structure MAY be used to announce the existence of certificates.
Note that this message is intended to be used for those cases (if
any) where there is no pre-existing method for publication of
certificates; it is not intended to be used where, for example, X.500
is the method for publication of certificates.
CertAnnContent ::= Certificate
5.3.15. Revocation Announcement
When a CA has revoked, or is about to revoke, a particular
certificate, it MAY issue an announcement of this (possibly upcoming)
event.
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RevAnnContent ::= SEQUENCE {
status PKIStatus,
certId CertId,
willBeRevokedAt GeneralizedTime,
badSinceDate GeneralizedTime,
crlDetails Extensions OPTIONAL
}
A CA MAY use such an announcement to warn (or notify) a subject that
its certificate is about to be (or has been) revoked. This would
typically be used where the request for revocation did not come from
the subject concerned.
The willBeRevokedAt field contains the time at which a new entry will
be added to the relevant CRLs.
5.3.16. CRL Announcement
When a CA issues a new CRL (or set of CRLs) the following data
structure MAY be used to announce this event.
CRLAnnContent ::= SEQUENCE OF CertificateList
5.3.17. PKI Confirmation Content
This data structure is used in the protocol exchange as the final
PKIMessage. Its content is the same in all cases -- actually there
is no content since the PKIHeader carries all the required
information.
PKIConfirmContent ::= NULL
Use of this message for certificate confirmation is NOT RECOMMENDED;
certConf SHOULD be used instead. Upon receiving a PKIConfirm for a
certificate response, the recipient MAY treat it as a certConf with
all certificates being accepted.
5.3.18. Certificate Confirmation Content
This data structure is used by the client to send a confirmation to
the CA/RA to accept or reject certificates.
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CertConfirmContent ::= SEQUENCE OF CertStatus
CertStatus ::= SEQUENCE {
certHash OCTET STRING,
certReqId INTEGER,
statusInfo PKIStatusInfo OPTIONAL,
hashAlg [0] AlgorithmIdentifier{DIGEST-ALGORITHM, {...}}
OPTIONAL
}
The hashAlg field SHOULD be used only in exceptional cases where the
signatureAlgorithm of the certificate to be confirmed does not
specify a hash algorithm in the OID or in the parameters or does not
define a hash algorithm to use with CMP, e.g., for EdDSA in [RFC9481]
Section 3.3). Otherwise, the certHash value SHALL be computed using
the same hash algorithm as used to create and verify the certificate
signature. If hashAlg is used, the CMP version indicated by the
certConf message header must be cmp2021(3).
For any particular CertStatus, omission of the statusInfo field
indicates ACCEPTANCE of the specified certificate. Alternatively,
explicit status details (with respect to acceptance or rejection) MAY
be provided in the statusInfo field, perhaps for auditing purposes at
the CA/RA.
Within CertConfirmContent, omission of a CertStatus structure
corresponding to a certificate supplied in the previous response
message indicates REJECTION of the certificate. Thus, an empty
CertConfirmContent (a zero-length SEQUENCE) MAY be used to indicate
rejection of all supplied certificates. See Section 5.2.8.3.2, for a
discussion of the certHash field with respect to proof-of-possession.
5.3.19. PKI General Message Content
InfoTypeAndValue ::= SEQUENCE {
infoType OBJECT IDENTIFIER,
infoValue ANY DEFINED BY infoType OPTIONAL
}
-- where {id-it} = {id-pkix 4} = {1 3 6 1 5 5 7 4}
GenMsgContent ::= SEQUENCE OF InfoTypeAndValue
5.3.19.1. CA Protocol Encryption Certificate
This MAY be used by the EE to get a certificate from the CA to use to
protect sensitive information during the protocol.
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GenMsg: {id-it 1}, < absent >
GenRep: {id-it 1}, Certificate | < absent >
EEs MUST ensure that the correct certificate is used for this
purpose.
5.3.19.2. Signing Key Pair Types
This MAY be used by the EE to get the list of signature algorithm
whose subject public key values the CA is willing to certify.
GenMsg: {id-it 2}, < absent >
GenRep: {id-it 2}, SEQUENCE SIZE (1..MAX) OF
AlgorithmIdentifier
Note: For the purposes of this exchange, rsaEncryption and
rsaWithSHA1, for example, are considered to be equivalent; the
question being asked is, "Is the CA willing to certify an RSA public
key?"
Note: In case several elliptic curves are supported, several id-
ecPublicKey elements as defined in [RFC5480] need to be given, one
per named curve.
5.3.19.3. Encryption/Key Agreement Key Pair Types
This MAY be used by the client to get the list of encryption/key
agreement algorithms whose subject public key values the CA is
willing to certify.
GenMsg: {id-it 3}, < absent >
GenRep: {id-it 3}, SEQUENCE SIZE (1..MAX) OF
AlgorithmIdentifier
Note: In case several elliptic curves are supported, several id-
ecPublicKey elements as defined in [RFC5480] need to be given, one
per named curve.
5.3.19.4. Preferred Symmetric Algorithm
This MAY be used by the client to get the CA-preferred symmetric
encryption algorithm for any confidential information that needs to
be exchanged between the EE and the CA (for example, if the EE wants
to send its private decryption key to the CA for archival purposes).
GenMsg: {id-it 4}, < absent >
GenRep: {id-it 4}, AlgorithmIdentifier
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5.3.19.5. Updated CA Key Pair
This MAY be used by the CA to announce a CA key update event.
GenMsg: {id-it 5}, CAKeyUpdAnnContent
5.3.19.6. CRL
This MAY be used by the client to get a copy of the latest CRL.
GenMsg: {id-it 6}, < absent >
GenRep: {id-it 6}, CertificateList
5.3.19.7. Unsupported Object Identifiers
This is used by the server to return a list of object identifiers
that it does not recognize or support from the list submitted by the
client.
GenRep: {id-it 7}, SEQUENCE SIZE (1..MAX) OF OBJECT IDENTIFIER
5.3.19.8. Key Pair Parameters
This MAY be used by the EE to request the domain parameters to use
for generating the key pair for certain public-key algorithms. It
can be used, for example, to request the appropriate P, Q, and G to
generate the DH/DSA key, or to request a set of well-known elliptic
curves.
GenMsg: {id-it 10}, OBJECT IDENTIFIER -- (Algorithm object-id)
GenRep: {id-it 11}, AlgorithmIdentifier | < absent >
An absent infoValue in the GenRep indicates that the algorithm
specified in GenMsg is not supported.
EEs MUST ensure that the parameters are acceptable to it and that the
GenRep message is authenticated (to avoid substitution attacks).
5.3.19.9. Revocation Passphrase
This MAY be used by the EE to send a passphrase to a CA/RA for the
purpose of authenticating a later revocation request (in the case
that the appropriate signing private key is no longer available to
authenticate the request). See Appendix B for further details on the
use of this mechanism.
GenMsg: {id-it 12}, EncryptedKey
GenRep: {id-it 12}, < absent >
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The use of EncryptedKey is described in Section 5.2.2.
5.3.19.10. ImplicitConfirm
See Section 5.1.1.1 for the definition and use of {id-it 13}.
5.3.19.11. ConfirmWaitTime
See Section 5.1.1.2 for the definition and use of {id-it 14}.
5.3.19.12. Original PKIMessage
See Section 5.1.1.3 for the definition and use of {id-it 15}.
5.3.19.13. Supported Language Tags
This MAY be used to determine the appropriate language tag to use in
subsequent messages. The sender sends its list of supported
languages (in order, most preferred to least); the receiver returns
the one it wishes to use. (Note: each UTF8String MUST include a
language tag.) If none of the offered tags are supported, an error
MUST be returned.
GenMsg: {id-it 16}, SEQUENCE SIZE (1..MAX) OF UTF8String
GenRep: {id-it 16}, SEQUENCE SIZE (1) OF UTF8String
5.3.19.14. CA Certificates
This MAY be used by the client to get CA certificates.
GenMsg: {id-it 17}, < absent >
GenRep: {id-it 17}, SEQUENCE SIZE (1..MAX) OF
CMPCertificate | < absent >
5.3.19.15. Root CA Update
This MAY be used by the client to get an update of a root CA
certificate, which is provided in the body of the request message.
In contrast to the ckuann message, this approach follows the request/
response model.
The EE SHOULD reference its current trust anchor in RootCaCertValue
in the request body, giving the root CA certificate if available.
GenMsg: {id-it 20}, RootCaCertValue | < absent >
GenRep: {id-it 18}, RootCaKeyUpdateContent | < absent >
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RootCaCertValue ::= CMPCertificate
RootCaKeyUpdateValue ::= RootCaKeyUpdateContent
RootCaKeyUpdateContent ::= SEQUENCE {
newWithNew CMPCertificate,
newWithOld [0] CMPCertificate OPTIONAL,
oldWithNew [1] CMPCertificate OPTIONAL
}
Note: In contrast to CAKeyUpdAnnContent, this type offers omitting
newWithOld and oldWithNew in the GenRep message, depending on the
needs of the EE.
5.3.19.16. Certificate Request Template
This MAY be used by the client to get a template containing
requirements for certificate request attributes and extensions. The
controls id-regCtrl-algId and id-regCtrl-rsaKeyLen MAY contain
details on the types of subject public keys the CA is willing to
certify.
The id-regCtrl-algId control MAY be used to identify a cryptographic
algorithm (see Section 4.1.2.7 of [RFC5280]) other than
rsaEncryption. The algorithm field SHALL identify a cryptographic
algorithm. The contents of the optional parameters field will vary
according to the algorithm identified. For example, when the
algorithm is set to id-ecPublicKey, the parameters identify the
elliptic curve to be used; see [RFC5480].
Note: The client may specify a profile name in the certProfile field,
see Section 5.1.1.4.
The id-regCtrl-rsaKeyLen control SHALL be used for algorithm
rsaEncryption and SHALL contain the intended modulus bit length of
the RSA key.
GenMsg: {id-it 19}, < absent >
GenRep: {id-it 19}, CertReqTemplateContent | < absent >
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CertReqTemplateValue ::= CertReqTemplateContent
CertReqTemplateContent ::= SEQUENCE {
certTemplate CertTemplate,
keySpec Controls OPTIONAL }
Controls ::= SEQUENCE SIZE (1..MAX) OF AttributeTypeAndValue
id-regCtrl-algId OBJECT IDENTIFIER ::= { iso(1)
identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) pkip(5) regCtrl(1) 11 }
AlgIdCtrl ::= AlgorithmIdentifier{ALGORITHM, {...}}
id-regCtrl-rsaKeyLen OBJECT IDENTIFIER ::= { iso(1)
identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) pkip(5) regCtrl(1) 12 }
RsaKeyLenCtrl ::= INTEGER (1..MAX)
The CertReqTemplateValue contains the prefilled certTemplate to be
used for a future certificate request. The publicKey field in the
certTemplate MUST NOT be used. In case the PKI management entity
wishes to specify supported public-key algorithms, the keySpec field
MUST be used. One AttributeTypeAndValue per supported algorithm or
RSA key length MUST be used.
Note: The controls ASN.1 type is defined in Section 6 of CRMF
[RFC4211]
5.3.19.17. CRL Update Retrieval
This MAY be used by the client to get new CRLs, specifying the source
of the CRLs and the thisUpdate value of the latest CRL it already
has, if available. A CRL source is given either by a
DistributionPointName or the GeneralNames of the issuing CA. The
DistributionPointName should be treated as an internal pointer to
identify a CRL that the server already has and not as a way to ask
the server to fetch CRLs from external locations. The server SHALL
only provide those CRLs that are more recent than the ones indicated
by the client.
GenMsg: {id-it 22}, SEQUENCE SIZE (1..MAX) OF CRLStatus
GenRep: {id-it 23}, SEQUENCE SIZE (1..MAX) OF
CertificateList | < absent >
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CRLSource ::= CHOICE {
dpn [0] DistributionPointName,
issuer [1] GeneralNames }
CRLStatus ::= SEQUENCE {
source CRLSource,
thisUpdate Time OPTIONAL }
5.3.19.18. KEM Ciphertext
This MAY be used by a PKI entity to get the KEM ciphertext for MAC-
based message protection using KEM (see Section 5.1.3.4).
The PKI entity which possesses a KEM key pair can request the
ciphertext by sending an InfoTypeAndValue structure of type
KemCiphertextInfo where the infoValue is absent. The ciphertext can
be provided in the following genp message with an InfoTypeAndValue
structure of the same type.
GenMsg: {id-it TBD1}, < absent >
GenRep: {id-it TBD1}, KemCiphertextInfo
KemCiphertextInfo ::= SEQUENCE {
kem AlgorithmIdentifier{KEM-ALGORITHM, {...}},
ct OCTET STRING
}
kem is the algorithm identifier of the KEM algorithm, and any
associated parameters, used to generate the ciphertext ct.
ct is the ciphertext output from the KEM Encapsulate function.
NOTE: These InfoTypeAndValue structures can also be transferred in
the generalInfo field of the PKIHeader in messages of other types
(see Section 5.1.1.5).
5.3.20. PKI General Response Content
GenRepContent ::= SEQUENCE OF InfoTypeAndValue
Examples of GenReps that MAY be supported include those listed in the
subsections of Section 5.3.19.
5.3.21. Error Message Content
This data structure MAY be used by EE, CA, or RA to convey error
information and by a PKI management entity to initiate delayed
delivery of responses.
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ErrorMsgContent ::= SEQUENCE {
pKIStatusInfo PKIStatusInfo,
errorCode INTEGER OPTIONAL,
errorDetails PKIFreeText OPTIONAL
}
This message MAY be generated at any time during a PKI transaction.
If the client sends this request, the server MUST respond with a
PKIConfirm response, or another ErrorMsg if any part of the header is
not valid.
In case a PKI management entity sends an error message to the EE with
the pKIStatusInfo field containing the status "waiting", the EE
SHOULD initiate polling as described in Section 5.3.22. If the EE
does not initiate polling, both sides MUST treat this message as the
end of the transaction (if a transaction is in progress).
If protection is desired on the message, the client MUST protect it
using the same technique (i.e., signature or MAC) as the starting
message of the transaction. The CA MUST always sign it with a
signature key.
5.3.22. Polling Request and Response
This pair of messages is intended to handle scenarios in which the
client needs to poll the server to determine the status of an
outstanding response (i.e., when the "waiting" PKIStatus has been
received).
PollReqContent ::= SEQUENCE OF SEQUENCE {
certReqId INTEGER }
PollRepContent ::= SEQUENCE OF SEQUENCE {
certReqId INTEGER,
checkAfter INTEGER, -- time in seconds
reason PKIFreeText OPTIONAL }
In response to an ir, cr, p10cr, or kur request message, polling is
initiated with an ip, cp, or kup response message containing status
"waiting". For any type of request message, polling can be initiated
with an error response messages with status "waiting". The following
clauses describe how polling messages are used. It is assumed that
multiple certConf messages can be sent during transactions. There
will be one sent in response to each ip, cp, or kup that contains a
CertStatus for an issued certificate.
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1 In response to an ip, cp, or kup message, an EE will send a
certConf for all issued certificates and expect a PKIconf for each
certConf. An EE will send a pollReq message in response to each
CertResponse element of an ip, cp, or kup message with status
"waiting" and in response to an error message with status
"waiting". Its certReqId MUST be either the index of a
CertResponse data structure with status "waiting" or -1 referring
to the complete response.
2 In response to a pollReq, a CA/RA will return an ip, cp, or kup if
one or more of still pending requested certificates are ready or
the final response to some other type of request is available;
otherwise, it will return a pollRep.
3 If the EE receives a pollRep, it will wait for at least the number
of seconds given in the checkAfter field before sending another
pollReq.
4 If the EE receives an ip, cp, or kup, then it will be treated in
the same way as the initial response; if it receives any other
response, then this will be treated as the final response to the
original request.
The following client-side state machine describes polling for
individual CertResponse elements.
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START
|
v
Send ir
| ip
v
Check status
of returned <------------------------+
certs |
| |
+------------------------>|<------------------+ |
| | | |
| (issued) v (waiting) | |
Add to <----------- Check CertResponse ------> Add to |
conf list for each certificate pending list |
/ |
/ |
(conf list) / (empty conf list) |
/ ip |
/ +-----------------+
(empty pending list) / | pollRep
END <---- Send certConf Send pollReq---------->Wait
| ^ ^ |
| | | |
+-----------------+ +---------------+
(pending list)
In the following exchange, the end entity is enrolling for two
certificates in one request.
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Step End Entity PKI
--------------------------------------------------------------------
1 Format ir
2 -> ir ->
3 Handle ir
4 Manual intervention is
required for both certs
5 <- ip <-
6 Process ip
7 Format pollReq
8 -> pollReq ->
9 Check status of cert requests
10 Certificates not ready
11 Format pollRep
12 <- pollRep <-
13 Wait
14 Format pollReq
15 -> pollReq ->
16 Check status of cert requests
17 One certificate is ready
18 Format ip
19 <- ip <-
20 Handle ip
21 Format certConf
22 -> certConf ->
23 Handle certConf
24 Format ack
25 <- pkiConf <-
26 Format pollReq
27 -> pollReq ->
28 Check status of certificate
29 Certificate is ready
30 Format ip
31 <- ip <-
31 Handle ip
32 Format certConf
33 -> certConf ->
34 Handle certConf
35 Format ack
36 <- pkiConf <-
The following client-side state machine describes polling for a
complete response message.
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Start
|
| Send request
|
+----------- Receive response ------------+
| |
| ip/cp/kup/error with | other
| status "waiting" | response
| |
v |
+------> Polling |
| | |
| | Send pollReq |
| | Receive response |
| | |
| pollRep | other response |
+-----------+------------------->+<-------------------+
|
v
Handle response
|
v
End
In the following exchange, the end entity is sending a general
message request, and the response is delayed by the server.
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Step End Entity PKI
--------------------------------------------------------------------
1 Format genm
2 -> genm ->
3 Handle genm
4 delay in response is necessary
5 Format error message "waiting"
with certReqId set to -1
6 <- error <-
7 Process error
8 Format pollReq
9 -> pollReq ->
10 Check status of original request
general message response not ready
11 Format pollRep
12 <- pollRep <-
13 Wait
14 Format pollReq
15 -> pollReq ->
16 Check status of original request
general message response is ready
17 Format genp
18 <- genp <-
19 Handle genp
6. Mandatory PKI Management Functions
Some of the PKI management functions outlined in Section 3.1 above
are described in this section.
This section deals with functions that are "mandatory" in the sense
that all end entity and CA/RA implementations MUST be able to provide
the functionality described. This part is effectively the profile of
the PKI management functionality that MUST be supported. Note,
however, that the management functions described in this section do
not need to be accomplished using the PKI messages defined in
Section 5 if alternate means are suitable for a given environment
(see [RFC9483] Section 7 and Appendix C for profiles of the
PKIMessages that MUST be supported).
6.1. Root CA Initialization
[See Section 3.1.1.2 for this document's definition of "root CA".]
A newly created root CA must produce a "self-certificate", which is a
Certificate structure with the profile defined for the "newWithNew"
certificate issued following a root CA key update.
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In order to make the CA's self certificate useful to end entities
that do not acquire the self certificate via "out-of-band" means, the
CA must also produce a fingerprint for its certificate. End entities
that acquire this fingerprint securely via some "out-of-band" means
can then verify the CA's self-certificate and, hence, the other
attributes contained therein.
The data structure used to carry the fingerprint is the OOBCertHash,
see Section 5.2.5.
6.2. Root CA Key Update
CA keys (as all other keys) have a finite lifetime and will have to
be updated on a periodic basis. The certificates NewWithNew,
NewWithOld, and OldWithNew (see Section 4.4.1) MAY be issued by the
CA to aid existing end entities who hold the current self-signed CA
certificate (OldWithOld) to transition securely to the new self-
signed CA certificate (NewWithNew), and to aid new end entities who
will hold NewWithNew to acquire OldWithOld securely for verification
of existing data.
6.3. Subordinate CA Initialization
[See Section 3.1.1.2 for this document's definition of "subordinate
CA".]
From the perspective of PKI management protocols, the initialization
of a subordinate CA is the same as the initialization of an end
entity. The only difference is that the subordinate CA must also
produce an initial revocation list.
6.4. CRL production
Before issuing any certificates, a newly established CA (which issues
CRLs) must produce "empty" versions of each CRL which are to be
periodically produced.
6.5. PKI Information Request
When a PKI entity (CA, RA, or EE) wishes to acquire information about
the current status of a CA, it MAY send that CA a request for such
information.
The CA MUST respond to the request by providing (at least) all of the
information requested by the requester. If some of the information
cannot be provided, then an error must be conveyed to the requester.
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If PKIMessages are used to request and supply this PKI information,
then the request MUST be the GenMsg message, the response MUST be the
GenRep message, and the error MUST be the Error message. These
messages are protected using a MAC based on shared secret information
(i.e., password-based MAC, see CMP Algorithms [RFC9481] Section 6.1)
or a signature(if the end entity has an existing certificate).
6.6. Cross Certification
The requester CA is the CA that will become the subject of the cross-
certificate; the responder CA will become the issuer of the cross-
certificate.
The requester CA must be "up and running" before initiating the
cross-certification operation.
6.6.1. One-Way Request-Response Scheme:
The cross-certification scheme is essentially a one way operation;
that is, when successful, this operation results in the creation of
one new cross-certificate. If the requirement is that cross-
certificates be created in "both directions", then each CA, in turn,
must initiate a cross-certification operation (or use another
scheme).
This scheme is suitable where the two CAs in question can already
verify each other's signatures (they have some common points of
trust) or where there is an out-of-band verification of the origin of
the certification request.
Detailed Description:
Cross certification is initiated at one CA known as the responder.
The CA administrator for the responder identifies the CA it wants to
cross certify and the responder CA equipment generates an
authorization code. The responder CA administrator passes this
authorization code by out-of-band means to the requester CA
administrator. The requester CA administrator enters the
authorization code at the requester CA in order to initiate the on-
line exchange.
The authorization code is used for authentication and integrity
purposes. This is done by generating a symmetric key based on the
authorization code and using the symmetric key for generating Message
Authentication Codes (MACs) on all messages exchanged.
(Authentication may alternatively be done using signatures instead of
MACs, if the CAs are able to retrieve and validate the required
public keys by some means, such as an out-of-band hash comparison.)
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The requester CA initiates the exchange by generating a cross-
certification request (ccr) with a fresh random number (requester
random number). The requester CA then sends the ccr message to the
responder CA. The fields in this message are protected from
modification with a MAC based on the authorization code.
Upon receipt of the ccr message, the responder CA validates the
message and the MAC, saves the requester random number, and generates
its own random number (responder random number). It then generates
(and archives, if desired) a new requester certificate that contains
the requester CA public key and is signed with the responder CA
signature private key. The responder CA responds with the cross
certification response (ccp) message. The fields in this message are
protected from modification with a MAC based on the authorization
code.
Upon receipt of the ccp message, the requester CA validates the
message (including the received random numbers) and the MAC. The
requester CA responds with the certConf message. The fields in this
message are protected from modification with a MAC based on the
authorization code. The requester CA MAY write the requester
certificate to the Repository as an aid to later certificate path
construction.
Upon receipt of the certConf message, the responder CA validates the
message and the MAC, and sends back an acknowledgement using the
PKIConfirm message. It MAY also publish the requester certificate as
an aid to later path construction.
Notes:
1. The ccr message must contain a "complete" certification request;
that is, all fields except the serial number (including, e.g., a
BasicConstraints extension) must be specified by the requester
CA.
2. The ccp message SHOULD contain the verification certificate of
the responder CA; if present, the requester CA must then verify
this certificate (for example, via the "out-of-band" mechanism).
(A simpler, non-interactive model of cross-certification may also be
envisioned, in which the issuing CA acquires the subject CA's public
key from some repository, verifies it via some out-of-band mechanism,
and creates and publishes the cross-certificate without the subject
CA's explicit involvement. This model may be perfectly legitimate
for many environments, but since it does not require any protocol
message exchanges, its detailed description is outside the scope of
this specification.)
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6.7. End Entity Initialization
As with CAs, end entities must be initialized. Initialization of end
entities requires at least two steps:
* acquisition of PKI information
* out-of-band verification of one root-CA public key
(other possible steps include the retrieval of trust condition
information and/or out-of-band verification of other CA public keys).
6.7.1. Acquisition of PKI Information
The information REQUIRED is:
* the current root-CA public key
* (if the certifying CA is not a root-CA) the certification path
from the root CA to the certifying CA together with appropriate
revocation lists
* the algorithms and algorithm parameters that the certifying CA
supports for each relevant usage
Additional information could be required (e.g., supported extensions
or CA policy information) in order to produce a certification request
that will be successful. However, for simplicity we do not mandate
that the end entity acquires this information via the PKI messages.
The end result is simply that some certification requests may fail
(e.g., if the end entity wants to generate its own encryption key,
but the CA doesn't allow that).
The required information MAY be acquired as described in Section 6.5.
6.7.2. Out-of-Band Verification of Root-CA Key
An end entity must securely possess the public key of its root CA.
One method to achieve this is to provide the end entity with the CA's
self-certificate fingerprint via some secure "out-of-band" means.
The end entity can then securely use the CA's self-certificate.
See Section 6.1 for further details.
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6.8. Certificate Request
An initialized end entity MAY request an additional certificate at
any time (for any purpose). This request will be made using the
certification request (cr) message. If the end entity already
possesses a signing key pair (with a corresponding verification
certificate), then this cr message will typically be protected by the
entity's digital signature. The CA returns the new certificate (if
the request is successful) in a CertRepMessage.
6.9. Key Update
When a key pair is due to expire, the relevant end entity MAY request
a key update; that is, it MAY request that the CA issue a new
certificate for a new key pair (or, in certain circumstances, a new
certificate for the same key pair). The request is made using a key
update request (kur) message (referred to, in some environments, as a
"Certificate Update" operation). If the end entity already possesses
a signing key pair (with a corresponding verification certificate),
then this message will typically be protected by the entity's digital
signature. The CA returns the new certificate (if the request is
successful) in a key update response (kup) message, which is
syntactically identical to a CertRepMessage.
7. Version Negotiation
This section defines the version negotiation used to support older
protocols between client and servers.
If a client knows the protocol version(s) supported by the server
(e.g., from a previous PKIMessage exchange or via some out-of-band
means), then it MUST send a PKIMessage with the highest version
supported by both it and the server. If a client does not know what
version(s) the server supports, then it MUST send a PKIMessage using
the highest version it supports with the following exception.
Version cmp2021 SHOULD only be used if cmp2021 syntax is needed for
the request being sent or for the expected response.
Note: Using cmp2000 as the default pvno is done to avoid extra
message exchanges for version negotiation and to foster compatibility
with cmp2000 implementations. Version cmp2021 syntax is only needed
if a message exchange uses hashAlg (in CertStatus) or EnvelopedData.
If a server receives a message with a version that it supports, then
the version of the response message MUST be the same as the received
version. If a server receives a message with a version higher or
lower than it supports, then it MUST send back an ErrorMsg with the
unsupportedVersion bit set (in the failureInfo field of the
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pKIStatusInfo). If the received version is higher than the highest
supported version, then the version in the error message MUST be the
highest version the server supports; if the received version is lower
than the lowest supported version then the version in the error
message MUST be the lowest version the server supports.
If a client gets back an ErrorMsgContent with the unsupportedVersion
bit set and a version it supports, then it MAY retry the request with
that version.
7.1. Supporting RFC 2510 Implementations
RFC 2510 did not specify the behavior of implementations receiving
versions they did not understand since there was only one version in
existence. With the introduction of the revision in [RFC4210], the
following versioning behaviour is recommended.
7.1.1. Clients Talking to RFC 2510 Servers
If, after sending a message with a protocol version number higher
than cmp1999, a client receives an ErrorMsgContent with a version of
cmp1999, then it MUST abort the current transaction.
If a client receives a non-error PKIMessage with a version of
cmp1999, then it MAY decide to continue the transaction (if the
transaction hasn't finished) using RFC 2510 semantics. If it does
not choose to do so and the transaction is not finished, then it MUST
abort the transaction and send an ErrorMsgContent with a version of
cmp1999.
7.1.2. Servers Receiving Version cmp1999 PKIMessages
If a server receives a version cmp1999 message it MAY revert to RFC
2510 behaviour and respond with version cmp1999 messages. If it does
not choose to do so, then it MUST send back an ErrorMsgContent as
described above in Section 7.
8. Security Considerations
8.1. On the Necessity of Proof-Of-Possession
It is well established that the role of a Certification Authority is
to verify that the name and public key belong to the end entity prior
to issuing a certificate. On a deeper inspection however, it is not
entirely clear what security guarantees are lost if an end entity is
able to obtain a certificate containing a public key that they do not
possess the corresponding private key for. There are some scenarios,
described as "forwarding attacks" in Appendix A of [Gueneysu], in
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which this can lead to protocol attacks against a naively-implemented
sign-then-encrypt protocol, but in general it merely results in the
end entity obtaining a certificate that they can not use.
8.2. Proof-Of-Possession with a Decryption Key
Some cryptographic considerations are worth explicitly spelling out.
In the protocols specified above, when an end entity is required to
prove possession of a decryption key, it is effectively challenged to
decrypt something (its own certificate). This scheme (and many
others!) could be vulnerable to an attack if the possessor of the
decryption key in question could be fooled into decrypting an
arbitrary challenge and returning the cleartext to an attacker.
Although in this specification a number of other failures in security
are required in order for this attack to succeed, it is conceivable
that some future services (e.g., notary, trusted time) could
potentially be vulnerable to such attacks. For this reason, we
reiterate the general rule that implementations should be very
careful about decrypting arbitrary "ciphertext" and revealing
recovered "plaintext" since such a practice can lead to serious
security vulnerabilities.
The client MUST return the decrypted values only if they match the
expected content type. In an Indirect Method, the decrypted value
MUST be a valid certificate, and in the Direct Method, the decrypted
value MUST be a Rand as defined in Section 5.2.8.3.3.
8.3. Proof-Of-Possession by Exposing the Private Key
Note also that exposing a private key to the CA/RA as a proof-of-
possession technique can carry some security risks (depending upon
whether or not the CA/RA can be trusted to handle such material
appropriately). Implementers are advised to:
* Exercise caution in selecting and using this particular POP
mechanism
* When appropriate, have the user of the application explicitly
state that they are willing to trust the CA/RA to have a copy of
their private key before proceeding to reveal the private key.
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8.4. Attack Against Diffie-Hellman Key Exchange
A small subgroup attack during a Diffie-Hellman key exchange may be
carried out as follows. A malicious end entity may deliberately
choose D-H parameters that enable him/her to derive (a significant
number of bits of) the D-H private key of the CA during a key
archival or key recovery operation. Armed with this knowledge, the
EE would then be able to retrieve the decryption private key of
another unsuspecting end entity, EE2, during EE2's legitimate key
archival or key recovery operation with that CA. In order to avoid
the possibility of such an attack, two courses of action are
available. (1) The CA may generate a fresh D-H key pair to be used
as a protocol encryption key pair for each EE with which it
interacts. (2) The CA may enter into a key validation protocol (not
specified in this document) with each requesting end entity to ensure
that the EE's protocol encryption key pair will not facilitate this
attack. Option (1) is clearly simpler (requiring no extra protocol
exchanges from either party) and is therefore RECOMMENDED.
8.5. Perfect Forward Secrecy
Long-term security typically requires perfect forward secrecy (pfs).
When transferring encrypted long-term confidential values such as
centrally generated private keys or revocation passphrases, pfs
likely is important. Yet it is not needed for CMP message protection
providing integrity and authenticity because transfer of PKI messages
is usually completed in very limited time. For the same reason it
typically is not required for the indirect method of providing a POP
Section 5.2.8.3.2 delivering the newly issued certificate in
encrypted form.
Encrypted values Section 5.2.2 are transferred using CMS
EnvelopedData [RFC5652], which does not offer pfs. In cases where
long-term security is needed, CMP messages SHOULD be transferred over
a mechanism that provides pfs, such as TLS with appropriate cipher
suites selected.
8.6. Private Keys for Certificate Signing and CMP Message Protection
A CA should not reuse its certificate signing key for other purposes,
such as protecting CMP responses and TLS connections. This way,
exposure to other parts of the system and the number of uses of this
particularly critical key are reduced to a minimum.
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8.7. Entropy of Random Numbers, Key Pairs, and Shared Secret
Information
Implementations must generate nonces and private keys from random
input. The use of inadequate pseudorandom number generators (PRNGs)
to generate cryptographic keys can result in little or no security.
An attacker may find it much easier to reproduce the PRNG environment
that produced the keys and to search the resulting small set of
possibilities than brute-force searching the whole key space. As an
example of predictable random numbers, see [CVE-2008-0166];
consequences of low-entropy random numbers are discussed in Mining
Your Ps and Qs [MiningPsQs]. The generation of quality random
numbers is difficult. ISO/IEC 20543:2019 [ISO.20543-2019], NIST SP
800-90A Rev.1 [NIST.SP.800_90Ar1], BSI AIS 31 V2.0 [AIS31], and other
specifications offer valuable guidance in this area.
If shared secret information is generated by a cryptographically
secure random number generator (CSRNG), it is safe to assume that the
entropy of the shared secret information equals its bit length. If
no CSRNG is used, the entropy of shared secret information depends on
the details of the generation process and cannot be measured securely
after it has been generated. If user-generated passwords are used as
shared secret information, their entropy cannot be measured and are
typically insufficient for protected delivery of centrally generated
keys or trust anchors.
If the entropy of shared secret information protecting the delivery
of a centrally generated key pair is known, it should not be less
than the security strength of that key pair; if the shared secret
information is reused for different key pairs, the security of the
shared secret information should exceed the security strength of each
individual key pair.
For the case of a PKI management operation that delivers a new trust
anchor (e.g., a root CA certificate) using caPubs or genp that is (a)
not concluded in a timely manner or (b) where the shared secret
information is reused for several key management operations, the
entropy of the shared secret information, if known, should not be
less than the security strength of the trust anchor being managed by
the operation. The shared secret information should have an entropy
that at least matches the security strength of the key material being
managed by the operation. Certain use cases may require shared
secret information that may be of a low security strength, e.g., a
human-generated password. It is RECOMMENDED that such secret
information be limited to a single PKI management operation.
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Importantly for this section further information about algorithm use
profiles and their security strength is available in CMP Algorithms
[RFC9481] Section 7.
8.8. Recurring Usage of KEM Keys for Message Protection
For each PKI management operation using MAC-based message protection
involving KEM, see Section 5.1.3.4, the KEM Encapsulate() function,
providing a fresh KEM ciphertext (ct) and shared secret (ss), MUST be
invoked. This can be enforced by using senderNonce and recipNonce
header fields in all messages of the PKI management operation.
It is assumed that the overall data size of the CMP messages in a PKI
management operation protected by a single shared secret key is small
enough not to introduce extra security risks.
To be appropriate for use with this specification, the KEM algorithm
MUST explicitly be designed to be secure when the public key is used
many times. For example, a KEM algorithm with a single-use public
key is not appropriate because the public key is expected to be
carried in a long-lived certificate [RFC5280] and used over and over.
Thus, KEM algorithms that offer indistinguishability under adaptive
chosen ciphertext attack (IND-CCA2) security are appropriate. A
common design pattern for obtaining IND-CCA2 security with public key
reuse is to apply the Fujisaki-Okamoto (FO) transform [Fujisaki] or a
variant of the FO transform [Hofheinz].
Therefore, given a long-term public key using an IND-CCA2 secure KEM
algorithm, there is no limit to the number of CMP messages that can
be authenticated using KEM keys for MAC-based message protection.
8.9. Trust Anchor Provisioning Using CMP Messages
A provider of trust anchors, which may be an RA involved in
configuration management of its clients, MUST NOT include to-be-
trusted CA certificates in a CMP message unless the specific
deployment scenario can ensure that it is adequate that the receiving
EE trusts these certificates, e.g., by loading them into its trust
store.
Whenever an EE receives in a CMP message a CA certificate to be used
as a trust anchor (for example in the caPubs field of a certificate
response or in a general response), it MUST properly authenticate the
message sender with existing trust anchors without requiring new
trust anchor information included in the message.
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Additionally, the EE MUST verify that the sender is an authorized
source of trust anchors. This authorization is governed by local
policy and typically indicated using shared secret information or
with a signature-based message protection using a certificate issued
by a PKI that is explicitly authorized for this purpose.
8.10. Authorizing Requests for Certificates with Specific EKUs
When a CA issues a certificate containing extended key usage
extensions as defined in Section 4.5, this expresses delegation of an
authorization that originally is only with the CA certificate itself.
Such delegation is a very sensitive action in a PKI and therefore
special care must be taken when approving such certificate requests
to ensure that only legitimate entities receive a certificate
containing such an EKU.
8.11. Usage of Certificate Transparency Logs
CAs that support indirect POP MUST NOT also publish final
certificates to Certificate Transparency logs [RFC9162] before having
received the certConf message containing the certHash of that
certificate to complete the POP. The risk is that a malicious actor
could fetch the final certificate from the CT log and use that to
spoof a response to the implicit POP challenge via a certConf
response. This risk does not apply to CT precertificates, so those
are ok to publish.
If a certificate or its precertificate was published in a CT log it
must be revoked, if a required certConf message could not be
verified, especially when the implicit POP was used.
9. IANA Considerations
This document updates the ASN.1 modules of CMP Updates Appendix A.2
[RFC9480]. The OID TBD2 (id-mod-cmp2023-02) was registered in the
SMI Security for PKIX Module Identifier registry to identify the
updated ASN.1 module.
In the SMI-numbers registry "SMI Security for PKIX CMP Information
Types (1.3.6.1.5.5.7.4)" (see https://www.iana.org/assignments/smi-
numbers/smi-numbers.xhtml#smi-numbers-1.3.6.1.5.5.7.4) as defined in
[RFC7299] one addition has been performed.
One new entry has been added:
Decimal: TBD1
Description: id-it-KemCiphertextInfo
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Reference: [RFCXXXX]
The new OID 1.2.840.113533.7.66.16 was registered by Entrust for id-
KemBasedMac in the arch 1.2.840.113533.7.66. Entrust registered also
the OIDs for id-PasswordBasedMac and id-DHBasedMac there.
< ToDo: The new OID TBD3 for the ASN.1 module
KEMAlgorithmInformation-2023 will be defined in draft-ietf-lamps-cms-
kemri. >
10. Acknowledgements
The authors of this document wish to thank Carlisle Adams, Stephen
Farrell, Tomi Kause, and Tero Mononen, the original authors of
[RFC4210], for their work.
We also thank all reviewers of this document for their valuable
feedback.
11. References
11.1. Normative References
[RFC2985] Nystrom, M. and B. Kaliski, "PKCS #9: Selected Object
Classes and Attribute Types Version 2.0", RFC 2985,
DOI 10.17487/RFC2985, November 2000,
<https://www.rfc-editor.org/rfc/rfc2985>.
[RFC2986] Nystrom, M. and B. Kaliski, "PKCS #10: Certification
Request Syntax Specification Version 1.7", RFC 2986,
DOI 10.17487/RFC2986, November 2000,
<https://www.rfc-editor.org/rfc/rfc2986>.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
2003, <https://www.rfc-editor.org/rfc/rfc3629>.
[RFC4211] Schaad, J., "Internet X.509 Public Key Infrastructure
Certificate Request Message Format (CRMF)", RFC 4211,
DOI 10.17487/RFC4211, September 2005,
<https://www.rfc-editor.org/rfc/rfc4211>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/rfc/rfc5280>.
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[RFC5480] Turner, S., Brown, D., Yiu, K., Housley, R., and T. Polk,
"Elliptic Curve Cryptography Subject Public Key
Information", RFC 5480, DOI 10.17487/RFC5480, March 2009,
<https://www.rfc-editor.org/rfc/rfc5480>.
[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
RFC 5652, DOI 10.17487/RFC5652, September 2009,
<https://www.rfc-editor.org/rfc/rfc5652>.
[RFC5958] Turner, S., "Asymmetric Key Packages", RFC 5958,
DOI 10.17487/RFC5958, August 2010,
<https://www.rfc-editor.org/rfc/rfc5958>.
[RFC6402] Schaad, J., "Certificate Management over CMS (CMC)
Updates", RFC 6402, DOI 10.17487/RFC6402, November 2011,
<https://www.rfc-editor.org/rfc/rfc6402>.
[RFC8933] Housley, R., "Update to the Cryptographic Message Syntax
(CMS) for Algorithm Identifier Protection", RFC 8933,
DOI 10.17487/RFC8933, October 2020,
<https://www.rfc-editor.org/rfc/rfc8933>.
[RFC9045] Housley, R., "Algorithm Requirements Update to the
Internet X.509 Public Key Infrastructure Certificate
Request Message Format (CRMF)", RFC 9045,
DOI 10.17487/RFC9045, June 2021,
<https://www.rfc-editor.org/rfc/rfc9045>.
[RFC9481] Brockhaus, H., Aschauer, H., Ounsworth, M., and J. Gray,
"Certificate Management Protocol (CMP) Algorithms",
RFC 9481, DOI 10.17487/RFC9481, November 2023,
<https://www.rfc-editor.org/rfc/rfc9481>.
[I-D.ietf-lamps-cms-kemri]
Housley, R., Gray, J., and T. Okubo, "Using Key
Encapsulation Mechanism (KEM) Algorithms in the
Cryptographic Message Syntax (CMS)", Work in Progress,
Internet-Draft, draft-ietf-lamps-cms-kemri-08, 6 February
2024, <https://datatracker.ietf.org/doc/html/draft-ietf-
lamps-cms-kemri-08>.
[ITU.X509.2000]
International Telecommunications Union, "Information
technology - Open Systems Interconnection - The Directory:
Public-key and attribute certificate frameworks",
ITU-T Recommendation X.509, ISO Standard 9594-8, March
2000.
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[MvOV97] Menezes, A., van Oorschot, P., and S. Vanstone, "Handbook
of Applied Cryptography", CRC Press ISBN 0-8493-8523-7,
1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
11.2. Informative References
[RFC9480] Brockhaus, H., von Oheimb, D., and J. Gray, "Certificate
Management Protocol (CMP) Updates", RFC 9480,
DOI 10.17487/RFC9480, November 2023,
<https://www.rfc-editor.org/rfc/rfc9480>.
[RFC9482] Sahni, M., Ed. and S. Tripathi, Ed., "Constrained
Application Protocol (CoAP) Transfer for the Certificate
Management Protocol", RFC 9482, DOI 10.17487/RFC9482,
November 2023, <https://www.rfc-editor.org/rfc/rfc9482>.
[RFC9483] Brockhaus, H., von Oheimb, D., and S. Fries, "Lightweight
Certificate Management Protocol (CMP) Profile", RFC 9483,
DOI 10.17487/RFC9483, November 2023,
<https://www.rfc-editor.org/rfc/rfc9483>.
[I-D.ietf-lamps-rfc6712bis]
Brockhaus, H., von Oheimb, D., Ounsworth, M., and J. Gray,
"Internet X.509 Public Key Infrastructure -- HTTP Transfer
for the Certificate Management Protocol (CMP)", Work in
Progress, Internet-Draft, draft-ietf-lamps-rfc6712bis-03,
10 February 2023, <https://datatracker.ietf.org/doc/html/
draft-ietf-lamps-rfc6712bis-03>.
[RFC1847] Galvin, J., Murphy, S., Crocker, S., and N. Freed,
"Security Multiparts for MIME: Multipart/Signed and
Multipart/Encrypted", RFC 1847, DOI 10.17487/RFC1847,
October 1995, <https://www.rfc-editor.org/rfc/rfc1847>.
[RFC2510] Adams, C. and S. Farrell, "Internet X.509 Public Key
Infrastructure Certificate Management Protocols",
RFC 2510, DOI 10.17487/RFC2510, March 1999,
<https://www.rfc-editor.org/rfc/rfc2510>.
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[RFC2585] Housley, R. and P. Hoffman, "Internet X.509 Public Key
Infrastructure Operational Protocols: FTP and HTTP",
RFC 2585, DOI 10.17487/RFC2585, May 1999,
<https://www.rfc-editor.org/rfc/rfc2585>.
[RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen,
"Internet X.509 Public Key Infrastructure Certificate
Management Protocol (CMP)", RFC 4210,
DOI 10.17487/RFC4210, September 2005,
<https://www.rfc-editor.org/rfc/rfc4210>.
[RFC4212] Blinov, M. and C. Adams, "Alternative Certificate Formats
for the Public-Key Infrastructure Using X.509 (PKIX)
Certificate Management Protocols", RFC 4212,
DOI 10.17487/RFC4212, October 2005,
<https://www.rfc-editor.org/rfc/rfc4212>.
[RFC4511] Sermersheim, J., Ed., "Lightweight Directory Access
Protocol (LDAP): The Protocol", RFC 4511,
DOI 10.17487/RFC4511, June 2006,
<https://www.rfc-editor.org/rfc/rfc4511>.
[RFC5912] Hoffman, P. and J. Schaad, "New ASN.1 Modules for the
Public Key Infrastructure Using X.509 (PKIX)", RFC 5912,
DOI 10.17487/RFC5912, June 2010,
<https://www.rfc-editor.org/rfc/rfc5912>.
[RFC7299] Housley, R., "Object Identifier Registry for the PKIX
Working Group", RFC 7299, DOI 10.17487/RFC7299, July 2014,
<https://www.rfc-editor.org/rfc/rfc7299>.
[RFC8649] Housley, R., "Hash Of Root Key Certificate Extension",
RFC 8649, DOI 10.17487/RFC8649, August 2019,
<https://www.rfc-editor.org/rfc/rfc8649>.
[RFC9162] Laurie, B., Messeri, E., and R. Stradling, "Certificate
Transparency Version 2.0", RFC 9162, DOI 10.17487/RFC9162,
December 2021, <https://www.rfc-editor.org/rfc/rfc9162>.
[NIST.SP.800_90Ar1]
Barker, E. B., Kelsey, J. M., and NIST, "Recommendation
for Random Number Generation Using Deterministic Random
Bit Generators", NIST Special Publications
(General) 800-90Ar1, DOI 10.6028/NIST.SP.800-90Ar1, June
2015,
<https://nvlpubs.nist.gov/nistpubs/SpecialPublications/
NIST.SP.800-90Ar1.pdf>.
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[IEEE.802.1AR-2018]
"IEEE Standard for Local and Metropolitan Area Networks -
Secure Device Identity", IEEE,
DOI 10.1109/ieeestd.2018.8423794, ISBN ["9781504450195"],
July 2018, <https://doi.org/10.1109/ieeestd.2018.8423794>.
[CVE-2008-0166]
National Institute of Science and Technology (NIST),
"National Vulnerability Database - CVE-2008-0166", May
2008, <https://nvd.nist.gov/vuln/detail/CVE-2008-0166>.
[MiningPsQs]
Security'12: Proceedings of the 21st USENIX conference on
Security symposium, Heninger, N., Durumeric, Z., Wustrow,
E., and J. A. Halderman, "Mining Your Ps and Qs: Detection
of Widespread Weak Keys in Network Devices", August 2012,
<https://www.usenix.org/conference/usenixsecurity12/
technical-sessions/presentation/heninger>.
[ISO.20543-2019]
International Organization for Standardization (ISO),
"Information technology -- Security techniques -- Test and
analysis methods for random bit generators within ISO/IEC
19790 and ISO/IEC 15408", ISO Draft Standard 20543-2019,
October 2019.
[AIS31] Bundesamt fuer Sicherheit in der Informationstechnik
(BSI), Killmann, W., and W. Schindler, "A proposal for:
Functionality classes for random number generators,
version 2.0", September 2011,
<https://www.bsi.bund.de/SharedDocs/Downloads/DE/BSI/
Zertifizierung/Interpretationen/AIS_31_Functionality_class
es_for_random_number_generators_e.pdf>.
[Gueneysu] Gueneysu, T., Hodges, P., Land, G., Ounsworth, M.,
Stebila, D., and G. Zaverucha, "Proof-of-possession for
KEM certificates using verifiable generation", Cryptology
ePrint Archive , 2022, <https://eprint.iacr.org/2022/703>.
[Fujisaki] Fujisaki, E. and T. Okamoto, "Secure Integration of
Asymmetric and Symmetric Encryption Schemes", Springer
Science and Business Media LLC, Journal of Cryptology vol.
26, no. 1, pp. 80-101, DOI 10.1007/s00145-011-9114-1,
December 2011,
<https://doi.org/10.1007/s00145-011-9114-1>.
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[Hofheinz] Hofheinz, D., Hövelmanns, K., and E. Kiltz, "A Modular
Analysis of the Fujisaki-Okamoto Transformation", Springer
International Publishing, Theory of Cryptography pp.
341-371, DOI 10.1007/978-3-319-70500-2_12,
ISBN ["9783319704999", "9783319705002"], 2017,
<https://doi.org/10.1007/978-3-319-70500-2_12>.
Appendix A. Reasons for the Presence of RAs
The reasons that justify the presence of an RA can be split into
those that are due to technical factors and those which are
organizational in nature. Technical reasons include the following.
* If hardware tokens are in use, then not all end entities will have
the equipment needed to initialize these; the RA equipment can
include the necessary functionality (this may also be a matter of
policy).
* Some end entities may not have the capability to publish
certificates; again, the RA may be suitably placed for this.
* The RA will be able to issue signed revocation requests on behalf
of end entities associated with it, whereas the end entity may not
be able to do this (if the key pair is completely lost).
Some of the organizational reasons that argue for the presence of an
RA are the following.
* It may be more cost effective to concentrate functionality in the
RA equipment than to supply functionality to all end entities
(especially if special token initialization equipment is to be
used).
* Establishing RAs within an organization can reduce the number of
CAs required, which is sometimes desirable.
* RAs may be better placed to identify people with their
"electronic" names, especially if the CA is physically remote from
the end entity.
* For many applications, there will already be in place some
administrative structure so that candidates for the role of RA are
easy to find (which may not be true of the CA).
Further reasons relevant for automated machine-to-machine certificate
lifecycle management are available in the Lightweight CMP Profile
[RFC9483].
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Appendix B. The Use of Revocation Passphrase
A revocation request must incorporate suitable security mechanisms,
including proper authentication, in order to reduce the probability
of successful denial-of-service attacks. A digital signature or DH/
KEM-based message protection on the request -- REQUIRED to support
within this specification depending on the key type used if
revocation requests are supported -- can provide the authentication
required, but there are circumstances under which an alternative
mechanism may be desirable (e.g., when the private key is no longer
accessible and the entity wishes to request a revocation prior to re-
certification of another key pair). In order to accommodate such
circumstances, a password-based MAC, see CMP Algorithms [RFC9481]
Section 6.1, on the request is also REQUIRED to support within this
specification (subject to local security policy for a given
environment) if revocation requests are supported and if shared
secret information can be established between the requester and the
responder prior to the need for revocation.
A mechanism that has seen use in some environments is "revocation
passphrase", in which a value of sufficient entropy (i.e., a
relatively long passphrase rather than a short password) is shared
between (only) the entity and the CA/RA at some point prior to
revocation; this value is later used to authenticate the revocation
request.
In this specification, the following technique to establish shared
secret information (i.e., a revocation passphrase) is OPTIONAL to
support. Its precise use in CMP messages is as follows.
* The OID and value specified in Section 5.3.19.9 MAY be sent in a
GenMsg message at any time or MAY be sent in the generalInfo field
of the PKIHeader of any PKIMessage at any time. (In particular,
the EncryptedKey structure as described in Section 5.2.2 may be
sent in the header of the certConf message that confirms
acceptance of certificates requested in an initialization request
or certificate request message.) This conveys a revocation
passphrase chosen by the entity to the relevant CA/RA. When
EnvelopedData is used, this is in the decrypted bytes of
encryptedContent field. When EncryptedValue is used, this is in
the decrypted bytes of the encValue field. Furthermore, the
transfer is accomplished with appropriate confidentiality
characteristics.
* If a CA/RA receives the revocation passphrase (OID and value
specified in Section 5.3.19.9) in a GenMsg, it MUST construct and
send a GenRep message that includes the OID (with absent value)
specified in Section 5.3.19.9. If the CA/RA receives the
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revocation passphrase in the generalInfo field of a PKIHeader of
any PKIMessage, it MUST include the OID (with absent value) in the
generalInfo field of the PKIHeader of the corresponding response
PKIMessage. If the CA/RA is unable to return the appropriate
response message for any reason, it MUST send an error message
with a status of "rejection" and, optionally, a failInfo reason
set.
* Either the localKeyId attribute of EnvelopedData as specified in
[RFC2985] or the valueHint field of EncryptedValue MAY contain a
key identifier (chosen by the entity, along with the passphrase
itself) to assist in later retrieval of the correct passphrase
(e.g., when the revocation request is constructed by the end
entity and received by the CA/RA).
* The revocation request message is protected by a password-based
MAC, see CMP Algorithms [RFC9481] Section 6.1, with the revocation
passphrase as the key. If appropriate, the senderKID field in the
PKIHeader MAY contain the value previously transmitted in
localKeyId or valueHint.
Note: For a message transferring a revocation passphrase indicating
cmp2021(3) in the pvno field of the PKIHeader, the encrypted
passphrase MUST be transferred in the envelopedData choice of
EncryptedKey as defined in Section 5.2.2. When using cmp2000(2) in
the message header for backward compatibility, the encryptedValue is
used. This allows the necessary conveyance and protection of the
passphrase while maintaining bits-on-the-wire compatibility with
[RFC4210]. The encryaptedValue choice has been deprecated in favor
of encryptedData.
Using the technique specified above, the revocation passphrase may be
initially established and updated at any time without requiring extra
messages or out-of-band exchanges. For example, the revocation
request message itself (protected and authenticated through a MAC
that uses the revocation passphrase as a key) may contain, in the
PKIHeader, a new revocation passphrase to be used for authenticating
future revocation requests for any of the entity's other
certificates. In some environments this may be preferable to
mechanisms that reveal the passphrase in the revocation request
message, since this can allow a denial-of-service attack in which the
revealed passphrase is used by an unauthorized third party to
authenticate revocation requests on the entity's other certificates.
However, because the passphrase is not revealed in the request
message, there is no requirement that the passphrase must always be
updated when a revocation request is made (that is, the same
passphrase MAY be used by an entity to authenticate revocation
requests for different certificates at different times).
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Furthermore, the above technique can provide strong cryptographic
protection over the entire revocation request message even when a
digital signature is not used. Techniques that do authentication of
the revocation request by simply revealing the revocation passphrase
typically do not provide cryptographic protection over the fields of
the request message (so that a request for revocation of one
certificate may be modified by an unauthorized third party to a
request for revocation of another certificate for that entity).
Appendix C. PKI Management Message Profiles (REQUIRED)
This appendix contains detailed profiles for those PKIMessages that
MUST be supported by conforming implementations (see Section 6).
Note: Appendix C and D focus on PKI management operations managing
certificates for human end entities. In contrast, the Lightweight
CMP Profile [RFC9483] focuses on typical use cases of industrial and
IoT scenarios supporting highly automated certificate lifecycle
management scenarios.
Profiles for the PKIMessages used in the following PKI management
operations are provided:
* initial registration/certification
* basic authenticated scheme
* certificate request
* key update
C.1. General Rules for Interpretation of These Profiles.
1. Where OPTIONAL or DEFAULT fields are not mentioned in individual
profiles, they SHOULD be absent from the relevant message (i.e.,
a receiver can validly reject a message containing such fields as
being syntactically incorrect). Mandatory fields are not
mentioned if they have an obvious value (e.g., if not explicitly
stated, pvno is cmp2000(2)).
2. Where structures occur in more than one message, they are
separately profiled as appropriate.
3. The algorithmIdentifiers from PKIMessage structures are profiled
separately.
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4. A "special" X.500 DN is called the "NULL-DN"; this means a DN
containing a zero-length SEQUENCE OF RelativeDistinguishedNames
(its DER encoding is then '3000'H).
5. Where a GeneralName is required for a field, but no suitable
value is available (e.g., an end entity produces a request before
knowing its name), then the GeneralName is to be an X.500 NULL-DN
(i.e., the Name field of the CHOICE is to contain a NULL-DN).
This special value can be called a "NULL-GeneralName".
6. Where a profile omits to specify the value for a GeneralName,
then the NULL-GeneralName value is to be present in the relevant
PKIMessage field. This occurs with the sender field of the
PKIHeader for some messages.
7. Where any ambiguity arises due to naming of fields, the profile
names these using a "dot" notation (e.g., "certTemplate.subject"
means the subject field within a field called certTemplate).
8. Where a "SEQUENCE OF types" is part of a message, a zero-based
array notation is used to describe fields within the SEQUENCE OF
(e.g., crm[0].certReq.certTemplate.subject refers to a subfield
of the first CertReqMsg contained in a request message).
9. All PKI message exchanges in Appendix C.4 to C.6 require a
certConf message to be sent by the initiating entity and a
PKIConfirm to be sent by the responding entity. The PKIConfirm
is not included in some of the profiles given since its body is
NULL and its header contents are clear from the context. Any
authenticated means can be used for the protectionAlg (e.g.,
password-based MAC, if shared secret information is known, or
signature).
C.2. Algorithm Use Profile
For specifications of algorithm identifiers and respective
conventions for conforming implementations, please refer to
Section 7.1 of CMP Algorithms [RFC9481].
C.3. Proof-of-Possession Profile
POP fields for use (in signature field of pop field of
ProofOfPossession structure) when proving possession of a private
signing key that corresponds to a public verification key for which a
certificate has been requested.
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Field Value Comment
algorithmIdentifier MSG_SIG_ALG only signature protection is
allowed for this proof
signature present bits calculated using MSG_SIG_ALG
Note: For examples of MSG_SIG_ALG OIDs see CMP Algorithms Section 3
[RFC9481].
Proof-of-possession of a private decryption key that corresponds to a
public encryption key for which a certificate has been requested does
not use this profile; the CertHash field of the certConf message is
used instead.
Not every CA/RA will do Proof-of-Possession (of signing key,
decryption key, or key agreement key) in the PKIX-CMP in-band
certification request protocol (how POP is done MAY ultimately be a
policy issue that is made explicit for any given CA in its publicized
Policy OID and Certification Practice Statement). However, this
specification mandates that CA/RA entities MUST do POP (by some
means) as part of the certification process. All end entities MUST
be prepared to provide POP (i.e., these components of the PKIX-CMP
protocol MUST be supported).
C.4. Initial Registration/Certification (Basic Authenticated Scheme)
An (uninitialized) end entity requests a (first) certificate from a
CA. When the CA responds with a message containing a certificate,
the end entity replies with a certificate confirmation. The CA sends
a PKIConfirm back, closing the transaction. All messages are
authenticated.
This scheme allows the end entity to request certification of a
locally-generated public key (typically a signature key). The end
entity MAY also choose to request the centralized generation and
certification of another key pair (typically an encryption key pair).
Certification may only be requested for one locally generated public
key (for more, use separate PKIMessages).
The end entity MUST support proof-of-possession of the private key
associated with the locally-generated public key.
Preconditions:
1. The end entity can authenticate the CA's signature based on out-
of-band means
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2. The end entity and the CA share a symmetric MACing key
Message flow:
Step# End entity PKI
1 format ir
2 -> ir ->
3 handle ir
4 format ip
5 <- ip <-
6 handle ip
7 format certConf
8 -> certConf ->
9 handle certConf
10 format PKIConf
11 <- PKIConf <-
12 handle PKIConf
For this profile, we mandate that the end entity MUST include all
(i.e., one or two) CertReqMsg in a single PKIMessage, and that the
PKI (CA) MUST produce a single response PKIMessage that contains the
complete response (i.e., including the OPTIONAL second key pair, if
it was requested and if centralized key generation is supported).
For simplicity, we also mandate that this message MUST be the final
one (i.e., no use of "waiting" status value).
The end entity has an out-of-band interaction with the CA/RA. This
transaction established the shared secret, the referenceNumber and
OPTIONALLY the distinguished name used for both sender and subject
name in the certificate template. See Section 8.7 for security
considerations on quality of shared secret information.
Initialization Request -- ir
Field Value
recipient CA name
-- the name of the CA who is being asked to produce a certificate
protectionAlg MSG_MAC_ALG
-- only MAC protection is allowed for this request, based
-- on initial authentication key
senderKID referenceNum
-- the reference number which the CA has previously issued
-- to the end entity (together with the MACing key)
transactionID present
-- implementation-specific value, meaningful to end
-- entity.
-- [If already in use at the CA, then a rejection message MUST
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-- be produced by the CA]
senderNonce present
-- 128 (pseudo-)random bits
freeText any valid value
body ir (CertReqMessages)
only one or two CertReqMsg
are allowed
-- if more certificates are required, requests MUST be
-- packaged in separate PKIMessages
CertReqMsg one or two present
-- see below for details, note: crm[0] means the first
-- (which MUST be present), crm[1] means the second (which
-- is OPTIONAL, and used to ask for a centrally-generated key)
crm[0].certReq. fixed value of zero
certReqId
-- this is the index of the template within the message
crm[0].certReq present
certTemplate
-- MUST include subject public key value, otherwise unconstrained
crm[0].pop... optionally present if public key
POPOSigningKey from crm[0].certReq.certTemplate is
a signing key
-- proof-of-possession MAY be required in this exchange
-- (see Appendix D.3 for details)
crm[0].certReq. optionally present
controls.archiveOptions
-- the end entity MAY request that the locally-generated
-- private key be archived
crm[0].certReq. optionally present
controls.publicationInfo
-- the end entity MAY ask for publication of resulting cert.
crm[1].certReq fixed value of one
certReqId
-- the index of the template within the message
crm[1].certReq present
certTemplate
-- MUST NOT include actual public key bits, otherwise
-- unconstrained (e.g., the names need not be the same as in
-- crm[0]). Note that subjectPublicKeyInfo MAY be present
-- and contain an AlgorithmIdentifier followed by a
-- zero-length BIT STRING for the subjectPublicKey if it is
-- desired to inform the CA/RA of algorithm and parameter
-- preferences regarding the to-be-generated key pair.
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crm[1].certReq. present [object identifier MUST be
PROT_ENC_ALG]
controls.protocolEncrKey
-- if centralized key generation is supported by this CA,
-- this short-term asymmetric encryption key (generated by
-- the end entity) will be used by the CA to encrypt (a
-- symmetric key used to encrypt) a private key generated by
-- the CA on behalf of the end entity
crm[1].certReq. optionally present
controls.archiveOptions
crm[1].certReq. optionally present
controls.publicationInfo
protection present
-- bits calculated using MSG_MAC_ALG
Initialization Response -- ip
Field Value
sender CA name
-- the name of the CA who produced the message
messageTime present
-- time at which CA produced message
protectionAlg MSG_MAC_ALG
-- only MAC protection is allowed for this response
senderKID referenceNum
-- the reference number that the CA has previously issued to the
-- end entity (together with the MACing key)
transactionID present
-- value from corresponding ir message
senderNonce present
-- 128 (pseudo-)random bits
recipNonce present
-- value from senderNonce in corresponding ir message
freeText any valid value
body ip (CertRepMessage)
contains exactly one response
for each request
-- The PKI (CA) responds to either one or two requests as
-- appropriate. crc[0] denotes the first (always present);
-- crc[1] denotes the second (only present if the ir message
-- contained two requests and if the CA supports centralized
-- key generation).
crc[0]. fixed value of zero
certReqId
-- MUST contain the response to the first request in the
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-- corresponding ir message
crc[0].status. present, positive values allowed:
status "accepted", "grantedWithMods"
negative values allowed:
"rejection"
crc[0].status. present if and only if
failInfo crc[0].status.status is "rejection"
crc[0]. present if and only if
certifiedKeyPair crc[0].status.status is
"accepted" or "grantedWithMods"
certificate present unless end entity's public
key is an encryption key and POP
is done in this in-band exchange
encryptedCert present if and only if end entity's
public key is an encryption key and
POP done in this in-band exchange
publicationInfo optionally present
-- indicates where certificate has been published (present
-- at discretion of CA)
crc[1]. fixed value of one
certReqId
-- MUST contain the response to the second request in the
-- corresponding ir message
crc[1].status. present, positive values allowed:
status "accepted", "grantedWithMods"
negative values allowed:
"rejection"
crc[1].status. present if and only if
failInfo crc[0].status.status is "rejection"
crc[1]. present if and only if
certifiedKeyPair crc[0].status.status is "accepted"
or "grantedWithMods"
certificate present
privateKey present
-- Use EnvelopedData; if backward compatibility is required,
-- use EncryptedValue, see Section 5.2.2
publicationInfo optionally present
-- indicates where certificate has been published (present
-- at discretion of CA)
protection present
-- bits calculated using MSG_MAC_ALG
extraCerts optionally present
-- the CA MAY provide additional certificates to the end
-- entity
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Certificate confirm -- certConf
Field Value
sender present
-- same as in ir
recipient CA name
-- the name of the CA who was asked to produce a certificate
transactionID present
-- value from corresponding ir and ip messages
senderNonce present
-- 128 (pseudo-) random bits
recipNonce present
-- value from senderNonce in corresponding ip message
protectionAlg MSG_MAC_ALG
-- only MAC protection is allowed for this message. The
-- MAC is based on the initial authentication key shared
-- between the EE and the CA.
senderKID referenceNum
-- the reference number which the CA has previously issued
-- to the end entity (together with the MACing key)
body certConf
-- see Section 5.3.18, "PKI Confirmation Content", for the
-- contents of the certConf fields.
-- Note: two CertStatus structures are required if both an
-- encryption and a signing certificate were sent.
protection present
-- bits calculated using MSG_MAC_ALG
Confirmation -- PKIConf
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Field Value
sender present
-- same as in ip
recipient present
-- sender name from certConf
transactionID present
-- value from certConf message
senderNonce present
-- 128 (pseudo-) random bits
recipNonce present
-- value from senderNonce from certConf message
protectionAlg MSG_MAC_ALG
-- only MAC protection is allowed for this message.
senderKID referenceNum
body PKIConf
protection present
-- bits calculated using MSG_MAC_ALG
C.5. Certificate Request
An (initialized) end entity requests a certificate from a CA (for any
reason). When the CA responds with a message containing a
certificate, the end entity replies with a certificate confirmation.
The CA replies with a PKIConfirm, to close the transaction. All
messages are authenticated.
The profile for this exchange is identical to that given in
Appendix C.4, with the following exceptions:
* sender name SHOULD be present
* protectionAlg of MSG_SIG_ALG MUST be supported (MSG_MAC_ALG MAY
also be supported) in request, response, certConfirm, and
PKIConfirm messages;
* senderKID and recipKID are only present if required for message
verification;
* body is cr or cp;
* body may contain one or two CertReqMsg structures, but either
CertReqMsg may be used to request certification of a locally-
generated public key or a centrally-generated public key (i.e.,
the position-dependence requirement of Appendix C.4 is removed);
* protection bits are calculated according to the protectionAlg
field.
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C.6. Key Update Request
An (initialized) end entity requests a certificate from a CA (to
update the key pair and/or corresponding certificate that it already
possesses). When the CA responds with a message containing a
certificate, the end entity replies with a certificate confirmation.
The CA replies with a PKIConfirm, to close the transaction. All
messages are authenticated.
The profile for this exchange is identical to that given
inAppendix C.4, with the following exceptions:
1. sender name SHOULD be present
2. protectionAlg of MSG_SIG_ALG MUST be supported (MSG_MAC_ALG MAY
also be supported) in request, response, certConfirm, and
PKIConfirm messages;
3. senderKID and recipKID are only present if required for message
verification;
4. body is kur or kup;
5. body may contain one or two CertReqMsg structures, but either
CertReqMsg may be used to request certification of a locally-
generated public key or a centrally-generated public key
(i.e.,the position-dependence requirement of Appendix C.4 is
removed);
6. protection bits are calculated according to the protectionAlg
field;
7. regCtrl OldCertId SHOULD be used (unless it is clear to both
sender and receiver -- by means not specified in this document --
that it is not needed).
Appendix D. PKI Management Message Profiles (OPTIONAL)
This appendix contains detailed profiles for those PKIMessages that
MAY be supported by implementations.
Profiles for the PKIMessages used in the following PKI management
operations are provided:
* root CA key update
* information request/response
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* cross-certification request/response (1-way)
* in-band initialization using external identity certificate
Later versions of this document may extend the above to include
profiles for the operations listed below (along with other
operations, if desired).
* revocation request
* certificate publication
* CRL publication
D.1. General Rules for Interpretation of These Profiles.
Identical to Appendix C.1.
D.2. Algorithm Use Profile
Identical to Appendix C.2.
D.3. Self-Signed Certificates
Profile of how a Certificate structure may be "self-signed". These
structures are used for distribution of CA public keys. This can
occur in one of three ways (see Section 4.4 above for a description
of the use of these structures):
Type Function
-----------------------------------------------------------------
newWithNew a true "self-signed" certificate; the contained
public key MUST be usable to verify the signature
(though this provides only integrity and no
authentication whatsoever)
oldWithNew previous root CA public key signed with new private key
newWithOld new root CA public key signed with previous private key
Such certificates (including relevant extensions) must contain
"sensible" values for all fields. For example, when present,
subjectAltName MUST be identical to issuerAltName, and, when present,
keyIdentifiers must contain appropriate values, et cetera.
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D.4. Root CA Key Update
A root CA updates its key pair. It then produces a CA key update
announcement message that can be made available (via some transport
mechanism) to the relevant end entities. A confirmation message is
not required from the end entities.
ckuann message:
Field Value Comment
--------------------------------------------------------------
sender CA name CA name
body ckuann(CAKeyUpdAnnContent)
oldWithNew present see Appendix D.3 above
newWithOld present see Appendix D.3 above
newWithNew present see Appendix D.3 above
extraCerts optionally present can be used to "publish"
certificates (e.g.,
certificates signed using
the new private key)
D.5. PKI Information Request/Response
The end entity sends a general message to the PKI requesting details
that will be required for later PKI management operations. RA/CA
responds with a general response. If an RA generates the response,
then it will simply forward the equivalent message that it previously
received from the CA, with the possible addition of certificates to
the extraCerts fields of the PKIMessage. A confirmation message is
not required from the end entity.
Message Flows:
Step# End entity PKI
1 format genm
2 -> genm ->
3 handle genm
4 produce genp
5 <- genp <-
6 handle genp
genM:
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Field Value
recipient CA name
-- the name of the CA as contained in issuerAltName
-- extensions or issuer fields within certificates
protectionAlg MSG_MAC_ALG or MSG_SIG_ALG
-- any authenticated protection alg.
SenderKID present if required
-- must be present if required for verification of message
-- protection
freeText any valid value
body genr (GenReqContent)
GenMsgContent empty SEQUENCE
-- all relevant information requested
protection present
-- bits calculated using MSG_MAC_ALG or MSG_SIG_ALG
genP:
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Field Value
sender CA name
-- name of the CA which produced the message
protectionAlg MSG_MAC_ALG or MSG_SIG_ALG
-- any authenticated protection alg.
senderKID present if required
-- must be present if required for verification of message
-- protection
body genp (GenRepContent)
CAProtEncCert present (object identifier one
of PROT_ENC_ALG), with relevant
value
-- to be used if end entity needs to encrypt information for
-- the CA (e.g., private key for recovery purposes)
SignKeyPairTypes present, with relevant value
-- the set of signature algorithm identifiers that this CA will
-- certify for subject public keys
EncKeyPairTypes present, with relevant value
-- the set of encryption/key agreement algorithm identifiers that
-- this CA will certify for subject public keys
PreferredSymmAlg present (object identifier one
of PROT_SYM_ALG) , with relevant
value
-- the symmetric algorithm that this CA expects to be used
-- in later PKI messages (for encryption)
CAKeyUpdateInfo optionally present, with
relevant value
-- the CA MAY provide information about a relevant root CA
-- key pair using this field (note that this does not imply
-- that the responding CA is the root CA in question)
CurrentCRL optionally present, with relevant value
-- the CA MAY provide a copy of a complete CRL (i.e.,
-- fullest possible one)
protection present
-- bits calculated using MSG_MAC_ALG or MSG_SIG_ALG
extraCerts optionally present
-- can be used to send some certificates to the end
-- entity. An RA MAY add its certificate here.
D.6. Cross Certification Request/Response (1-way)
Creation of a single cross-certificate (i.e., not two at once). The
requesting CA MAY choose who is responsible for publication of the
cross-certificate created by the responding CA through use of the
PKIPublicationInfo control.
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Preconditions:
1. Responding CA can verify the origin of the request (possibly
requiring out-of-band means) before processing the request.
2. Requesting CA can authenticate the authenticity of the origin of
the response (possibly requiring out-of-band means) before
processing the response
The use of certificate confirmation and the corresponding server
confirmation is determined by the generalInfo field in the PKIHeader
(see Section 5.1.1). The following profile does not mandate support
for either confirmation.
Message Flows:
Step# Requesting CA Responding CA
1 format ccr
2 -> ccr ->
3 handle ccr
4 produce ccp
5 <- ccp <-
6 handle ccp
ccr:
Field Value
sender Requesting CA name
-- the name of the CA who produced the message
recipient Responding CA name
-- the name of the CA who is being asked to produce a certificate
messageTime time of production of message
-- current time at requesting CA
protectionAlg MSG_SIG_ALG
-- only signature protection is allowed for this request
senderKID present if required
-- must be present if required for verification of message
-- protection
recipKID present if required
-- must be present if required for verification of message
-- protection
transactionID present
-- implementation-specific value, meaningful to requesting CA.
-- [If already in use at responding CA then a rejection message
-- MUST be produced by responding CA]
senderNonce present
-- 128 (pseudo-)random bits
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freeText any valid value
body ccr (CertReqMessages)
only one CertReqMsg
allowed
-- if multiple cross certificates are required, they MUST be
-- packaged in separate PKIMessages
certTemplate present
-- details follow
version v1 or v3
-- v3 STRONGLY RECOMMENDED
signingAlg present
-- the requesting CA must know in advance with which algorithm it
-- wishes the certificate to be signed
subject present
-- may be NULL-DN only if subjectAltNames extension value proposed
validity present
-- MUST be completely specified (i.e., both fields present)
issuer present
-- may be NULL-DN only if issuerAltNames extension value proposed
publicKey present
-- the key to be certified (which must be for a signing algorithm)
extensions optionally present
-- a requesting CA must propose values for all extensions
-- that it requires to be in the cross-certificate
POPOSigningKey present
-- see Section D3: Proof-of-possession profile
protection present
-- bits calculated using MSG_SIG_ALG
extraCerts optionally present
-- MAY contain any additional certificates that requester wishes
-- to include
ccp:
Field Value
sender Responding CA name
-- the name of the CA who produced the message
recipient Requesting CA name
-- the name of the CA who asked for production of a certificate
messageTime time of production of message
-- current time at responding CA
protectionAlg MSG_SIG_ALG
-- only signature protection is allowed for this message
senderKID present if required
-- must be present if required for verification of message
-- protection
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recipKID present if required
transactionID present
-- value from corresponding ccr message
senderNonce present
-- 128 (pseudo-)random bits
recipNonce present
-- senderNonce from corresponding ccr message
freeText any valid value
body ccp (CertRepMessage)
only one CertResponse allowed
-- if multiple cross certificates are required they MUST be
-- packaged in separate PKIMessages
response present
status present
PKIStatusInfo.status present
-- if PKIStatusInfo.status is one of:
-- accepted, or
-- grantedWithMods,
-- then certifiedKeyPair MUST be present and failInfo MUST
-- be absent
failInfo present depending on
PKIStatusInfo.status
-- if PKIStatusInfo.status is:
-- rejection
-- then certifiedKeyPair MUST be absent and failInfo MUST be
-- present and contain appropriate bit settings
certifiedKeyPair present depending on
PKIStatusInfo.status
certificate present depending on
certifiedKeyPair
-- content of actual certificate must be examined by requesting CA
-- before publication
protection present
-- bits calculated using MSG_SIG_ALG
extraCerts optionally present
-- MAY contain any additional certificates that responder wishes
-- to include
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D.7. In-Band Initialization Using External Identity Certificate
An (uninitialized) end entity wishes to initialize into the PKI with
a CA, CA-1. It uses, for authentication purposes, a pre-existing
identity certificate issued by another (external) CA, CA-X. A trust
relationship must already have been established between CA-1 and CA-X
so that CA-1 can validate the EE identity certificate signed by CA-X.
Furthermore, some mechanism must already have been established within
the Personal Security Environment (PSE) of the EE that would allow it
to authenticate and verify PKIMessages signed by CA-1 (as one
example, the PSE may contain a certificate issued for the public key
of CA-1, signed by another CA that the EE trusts on the basis of out-
of-band authentication techniques).
The EE sends an initialization request to start the transaction.
When CA-1 responds with a message containing the new certificate, the
end entity replies with a certificate confirmation. CA-1 replies
with a PKIConfirm to close the transaction. All messages are signed
(the EE messages are signed using the private key that corresponds to
the public key in its external identity certificate; the CA-1
messages are signed using the private key that corresponds to the
public key in a
certificate that can be chained to a trust anchor in the EE's PSE).
The profile for this exchange is identical to that given in
Appendix C.4, with the following exceptions:
* the EE and CA-1 do not share a symmetric MACing key (i.e., there
is no out-of-band shared secret information between these
entities);
* sender name in ir MUST be present (and identical to the subject
name present in the external identity certificate);
* protectionAlg of MSG_SIG_ALG MUST be used in all messages;
* external identity cert. MUST be carried in ir extraCerts field
* senderKID and recipKID are not used;
* body is ir or ip;
* protection bits are calculated according to the protectionAlg
field.
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Appendix E. Variants of Using KEM Keys for PKI Message Protection
As described in Section 5.1.3.4, any party in a PKI management
operation may wish to use a KEM key pair for message protection.
Below possible cases are described.
For any PKI management operation started by a PKI entity with any
type of request message, the following message flows describe the use
of a KEM key. There are two cases to distinguish, namely whether the
PKI entity or the PKI management entity owns a KEM key pair. If both
sides own KEM key pairs, the flows need to be combined such that for
each direction a shared secret key is established.
In the following message flows Alice indicates the PKI entity that
uses a KEM key pair for message authentication and Bob provides the
KEM ciphertext using Alice's public KEM key, as described in
Section 5.1.3.4.
Message Flow when the PKI entity has a KEM key pair and certificate:
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Step# PKI entity PKI management entity
(Alice) (Bob)
1 format unprotected genm
of type
KemCiphertextInfo
without value, and
KEM certificate in
extraCerts
-> genm ->
2 validate KEM certificate
perform KEM Encapsulate
format unprotected genp
of type
KemCiphertextInfo
providing KEM ciphertext
<- genp <-
3 perform KEM Decapsulate
perform key derivation
to get ssk
format request with
MAC-based protection
-> request ->
4 perform key derivation
to get ssk
verify MAC-based
protection
-------- PKI entity authenticated by PKI management entity --------
format response with
protection depending on
available key material
<- response <-
5 verify protection
provided by the
PKI management entity
Further messages of this PKI management operation
can be exchanged with MAC-based protection by the PKI
entity using the established shared secret key (ssk)
Figure 3: Message Flow when PKI entity has a KEM key pair
Message Flow when the PKI entity knows that the PKI management entity
uses a KEM key pair and has the authentic public key:
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Step# PKI entity PKI management entity
(Bob) (Alice)
1 perform KEM Encapsulate
format request providing
KEM ciphertext in
generalInfo of type
KemCiphertextInfo,
and with protection
depending on available
key material
-> request ->
2 perform KEM Decapsulate
perform key derivation
to get ssk
format response with
MAC-based protection
<- response <-
3 perform key derivation
to get ssk
verify MAC-based
protection
-------- PKI management entity authenticated by PKI entity --------
Further messages of this PKI management operation
can be exchanged with MAC-based protection by the
PKI management entity using the established
shared secret key (ssk)
Figure 4: Message Flow when the PKI entity knows that the PKI
management entity uses a KEM key pair and has the authentic
public key
Note: Figure 4 describes the situation where KEM-based message
protection may not require more that one message exchange. In this
case, the transactionID MUST also be used by the PKI entity (Bob) to
ensure domain separation between different PKI management operations.
Message Flow when the PKI entity does not know that the PKI
management entity uses a KEM key pair:
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Step# PKI entity PKI management entity
(Bob) (Alice)
1 format request with
protection depending
on available key
material
-> request ->
2 format unprotected error
with status "rejection"
and failInfo
"wrongIntegrity" and KEM
certificate in
extraCerts
<- error <-
3 validate KEM certificate
proceed as shown in the Figure before
Figure 5: Message Flow when the PKI entity does not know that the PKI
management entity uses a KEM key pair
Appendix F. Compilable ASN.1 Definitions
This section contains the updated 2002 ASN.1 module for [RFC5912] as
updated in [RFC9480]. This module replaces the module in Section 9
of [RFC5912]. The module contains those changes to the normative
ASN.1 module from Appendix F of [RFC4210] that were specified in
[RFC9480], as well as changes made in this document.
PKIXCMP-2023
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-cmp2023-02(TBD2) }
DEFINITIONS EXPLICIT TAGS ::=
BEGIN
IMPORTS
AttributeSet{}, SingleAttribute{}, Extensions{}, EXTENSION, ATTRIBUTE
FROM PKIX-CommonTypes-2009
{iso(1) identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) id-mod(0) id-mod-pkixCommon-02(57)}
AlgorithmIdentifier{}, SIGNATURE-ALGORITHM, ALGORITHM,
DIGEST-ALGORITHM, MAC-ALGORITHM, KEY-DERIVATION
FROM AlgorithmInformation-2009
{iso(1) identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) id-mod(0)
id-mod-algorithmInformation-02(58)}
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Certificate, CertificateList, Time, id-kp
FROM PKIX1Explicit-2009
{iso(1) identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) id-mod(0) id-mod-pkix1-explicit-02(51)}
DistributionPointName, GeneralNames, GeneralName, KeyIdentifier
FROM PKIX1Implicit-2009
{iso(1) identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) id-mod(0) id-mod-pkix1-implicit-02(59)}
CertTemplate, PKIPublicationInfo, EncryptedKey, CertId,
CertReqMessages, Controls, RegControlSet, id-regCtrl
FROM PKIXCRMF-2009
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-crmf2005-02(55) }
-- The import of EncryptedKey is added due to the updates made
-- in [RFC9480]. EncryptedValue does not need to be imported
-- anymore and is therefore removed here.
CertificationRequest
FROM PKCS-10
{iso(1) identified-organization(3) dod(6) internet(1) security(5)
mechanisms(5) pkix(7) id-mod(0) id-mod-pkcs10-2009(69)}
-- (specified in [RFC2986] with 1993 ASN.1 syntax and IMPLICIT
-- tags). Alternatively, implementers may directly include
-- the syntax of [RFC2986] in this module.
localKeyId
FROM PKCS-9
{iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
modules(0) pkcs-9(1)}
-- The import of localKeyId is added due to the updates made in
-- [RFC9480]
EnvelopedData, SignedData
FROM CryptographicMessageSyntax-2009
{iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)
smime(16) modules(0) id-mod-cms-2004-02(41)}
-- The import of EnvelopedData and SignedData is added due to
-- the updates made in CMP Updates [RFC9480]
KEM-ALGORITHM
FROM KEMAlgorithmInformation-2023 -- [RFCFFFF]
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) id-mod(0)
id-mod-kemAlgorithmInformation-2023(TBD3) }
-- The import of KEM-ALGORITHM was added due to the updates made
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-- in [RFCXXXX]
-- RFC-Editor: Please set the new OID defined in
-- draft-ietf-lamps-cms-kemri as TBD3.
;
-- History of the PKIXCMP ASN.1 modules
-- [RFC2510]
-- 1988 Syntax, PKIXCMP, 1.3.6.1.5.5.7.0.9 (id-mod-cmp)
-- Obsoleted by RFC 4210 PKIXCMP, 1.3.6.1.5.5.7.0.16
-- (id-mod-cmp2000)
-- [RFC4210]
-- 1988 Syntax, PKIXCMP, 1.3.6.1.5.5.7.0.16 (id-mod-cmp2000)
-- Replaced by RFC 9480 PKIXCMP, 1.3.6.1.5.5.7.0.99
-- (id-mod-cmp2021-88)
-- [RFC5912]
-- 2002 Syntax, PKIXCMP-2009, 1.3.6.1.5.5.7.0.50
-- (id-mod-cmp2000-02)
-- Replaced by RFC 9480 PKIXCMP-2021, 1.3.6.1.5.5.7.0.100
-- (id-mod-cmp2021-02)
-- [RFC9480]
-- 1988 Syntax, PKIXCMP, 1.3.6.1.5.5.7.0.99 (id-mod-cmp2021-88)
-- 2002 Syntax, PKIXCMP-2021, 1.3.6.1.5.5.7.0.100
-- (id-mod-cmp2021-02)
-- Obsoleted by [RFCXXXX] PKIXCMP-2023, 1.3.6.1.5.5.7.0.TBD2
-- (id-mod-cmp2023-02)
-- [RFCXXXX]
-- 2002 Syntax, PKIXCMP-2023, 1.3.6.1.5.5.7.0.TBD2
-- (id-mod-cmp2023-02)
-- The rest of the module contains locally defined OIDs and
-- constructs:
CMPCertificate ::= CHOICE { x509v3PKCert Certificate, ... }
-- This syntax, while bits-on-the-wire compatible with the
-- standard X.509 definition of "Certificate", allows the
-- possibility of future certificate types (such as X.509
-- attribute certificates, card-verifiable certificates, or other
-- kinds of certificates) within this Certificate Management
-- Protocol, should a need ever arise to support such generality.
-- Those implementations that do not foresee a need to ever support
-- other certificate types MAY, if they wish, comment out the
-- above structure and "uncomment" the following one prior to
-- compiling this ASN.1 module. (Note that interoperability
-- with implementations that don't do this will be unaffected by
-- this change.)
-- CMPCertificate ::= Certificate
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PKIMessage ::= SEQUENCE {
header PKIHeader,
body PKIBody,
protection [0] PKIProtection OPTIONAL,
extraCerts [1] SEQUENCE SIZE (1..MAX) OF CMPCertificate
OPTIONAL }
PKIMessages ::= SEQUENCE SIZE (1..MAX) OF PKIMessage
PKIHeader ::= SEQUENCE {
pvno INTEGER { cmp1999(1), cmp2000(2),
cmp2021(3) },
sender GeneralName,
-- identifies the sender
recipient GeneralName,
-- identifies the intended recipient
messageTime [0] GeneralizedTime OPTIONAL,
-- time of production of this message (used when sender
-- believes that the transport will be "suitable", i.e.,
-- that the time will still be meaningful upon receipt)
protectionAlg [1] AlgorithmIdentifier{ALGORITHM, {...}}
OPTIONAL,
-- algorithm used for calculation of protection bits
senderKID [2] KeyIdentifier OPTIONAL,
recipKID [3] KeyIdentifier OPTIONAL,
-- to identify specific keys used for protection
transactionID [4] OCTET STRING OPTIONAL,
-- identifies the transaction, i.e., this will be the same in
-- corresponding request, response, certConf, and PKIConf
-- messages
senderNonce [5] OCTET STRING OPTIONAL,
recipNonce [6] OCTET STRING OPTIONAL,
-- nonces used to provide replay protection, senderNonce
-- is inserted by the creator of this message; recipNonce
-- is a nonce previously inserted in a related message by
-- the intended recipient of this message.
freeText [7] PKIFreeText OPTIONAL,
-- this may be used to indicate context-specific instructions
-- (this field is intended for human consumption)
generalInfo [8] SEQUENCE SIZE (1..MAX) OF
InfoTypeAndValue OPTIONAL
-- this may be used to convey context-specific information
-- (this field not primarily intended for human consumption)
}
PKIFreeText ::= SEQUENCE SIZE (1..MAX) OF UTF8String
-- text encoded as UTF-8 string [RFC3629]
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PKIBody ::= CHOICE { -- message-specific body elements
ir [0] CertReqMessages, --Initialization Request
ip [1] CertRepMessage, --Initialization Response
cr [2] CertReqMessages, --Certification Request
cp [3] CertRepMessage, --Certification Response
p10cr [4] CertificationRequest, --imported from [RFC2986]
popdecc [5] POPODecKeyChallContent, --pop Challenge
popdecr [6] POPODecKeyRespContent, --pop Response
kur [7] CertReqMessages, --Key Update Request
kup [8] CertRepMessage, --Key Update Response
krr [9] CertReqMessages, --Key Recovery Request
krp [10] KeyRecRepContent, --Key Recovery Response
rr [11] RevReqContent, --Revocation Request
rp [12] RevRepContent, --Revocation Response
ccr [13] CertReqMessages, --Cross-Cert. Request
ccp [14] CertRepMessage, --Cross-Cert. Response
ckuann [15] CAKeyUpdAnnContent, --CA Key Update Ann.
cann [16] CertAnnContent, --Certificate Ann.
rann [17] RevAnnContent, --Revocation Ann.
crlann [18] CRLAnnContent, --CRL Announcement
pkiconf [19] PKIConfirmContent, --Confirmation
nested [20] NestedMessageContent, --Nested Message
genm [21] GenMsgContent, --General Message
genp [22] GenRepContent, --General Response
error [23] ErrorMsgContent, --Error Message
certConf [24] CertConfirmContent, --Certificate Confirm
pollReq [25] PollReqContent, --Polling Request
pollRep [26] PollRepContent --Polling Response
}
PKIProtection ::= BIT STRING
ProtectedPart ::= SEQUENCE {
header PKIHeader,
body PKIBody }
id-PasswordBasedMac OBJECT IDENTIFIER ::= { iso(1) member-body(2)
usa(840) nt(113533) nsn(7) algorithms(66) 13 }
PBMParameter ::= SEQUENCE {
salt OCTET STRING,
-- Note: Implementations MAY wish to limit acceptable sizes
-- of this string to values appropriate for their environment
-- in order to reduce the risk of denial-of-service attacks.
owf AlgorithmIdentifier{DIGEST-ALGORITHM, {...}},
-- AlgId for the One-Way Function
iterationCount INTEGER,
-- number of times the OWF is applied
-- Note: Implementations MAY wish to limit acceptable sizes
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-- of this integer to values appropriate for their environment
-- in order to reduce the risk of denial-of-service attacks.
mac AlgorithmIdentifier{MAC-ALGORITHM, {...}}
-- AlgId of the Message Authentication Code algorithm
}
id-DHBasedMac OBJECT IDENTIFIER ::= { iso(1) member-body(2)
usa(840) nt(113533) nsn(7) algorithms(66) 30 }
DHBMParameter ::= SEQUENCE {
owf AlgorithmIdentifier{DIGEST-ALGORITHM, {...}},
-- AlgId for a One-Way Function
mac AlgorithmIdentifier{MAC-ALGORITHM, {...}}
-- AlgId of the Message Authentication Code algorithm
}
-- id-KemBasedMac and KemBMParameter were added in [RFCXXXX]
id-KemBasedMac OBJECT IDENTIFIER ::= { iso(1) member-body(2)
usa(840) nt(113533) nsn(7) algorithms(66) TBD4 }
KemBMParameter ::= SEQUENCE {
kdf AlgorithmIdentifier{KEY-DERIVATION, {...}},
-- AlgId of the Key Derivation Function algorithm
kemContext [0] OCTET STRING OPTIONAL,
-- MAY contain additional algorithm specific context information
len INTEGER (1..MAX),
-- Defines the length of the keying material output of the KDF
-- SHOULD be the maximum key length of the MAC function
mac AlgorithmIdentifier{MAC-ALGORITHM, {...}}
-- AlgId of the Message Authentication Code algorithm
}
PKIStatus ::= INTEGER {
accepted (0),
-- you got exactly what you asked for
grantedWithMods (1),
-- you got something like what you asked for; the
-- requester is responsible for ascertaining the differences
rejection (2),
-- you don't get it, more information elsewhere in the message
waiting (3),
-- the request body part has not yet been processed; expect to
-- hear more later (note: proper handling of this status
-- response MAY use the polling req/rep PKIMessages specified
-- in Section 5.3.22; alternatively, polling in the underlying
-- transport layer MAY have some utility in this regard)
revocationWarning (4),
-- this message contains a warning that a revocation is
-- imminent
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revocationNotification (5),
-- notification that a revocation has occurred
keyUpdateWarning (6)
-- update already done for the oldCertId specified in
-- CertReqMsg
}
PKIFailureInfo ::= BIT STRING {
-- since we can fail in more than one way!
-- More codes may be added in the future if/when required.
badAlg (0),
-- unrecognized or unsupported algorithm identifier
badMessageCheck (1),
-- integrity check failed (e.g., signature did not verify)
badRequest (2),
-- transaction not permitted or supported
badTime (3),
-- messageTime was not sufficiently close to the system time,
-- as defined by local policy
badCertId (4),
-- no certificate could be found matching the provided criteria
badDataFormat (5),
-- the data submitted has the wrong format
wrongAuthority (6),
-- the authority indicated in the request is different from the
-- one creating the response token
incorrectData (7),
-- the requester's data is incorrect (for notary services)
missingTimeStamp (8),
-- when the timestamp is missing but should be there
-- (by policy)
badPOP (9),
-- the proof-of-possession failed
certRevoked (10),
-- the certificate has already been revoked
certConfirmed (11),
-- the certificate has already been confirmed
wrongIntegrity (12),
-- KEM ciphertext missing for MAC-based protection of response,
-- or not valid integrity of message received (password based
-- instead of signature or vice versa)
badRecipientNonce (13),
-- not valid recipient nonce, either missing or wrong value
timeNotAvailable (14),
-- the TSA's time source is not available
unacceptedPolicy (15),
-- the requested TSA policy is not supported by the TSA
unacceptedExtension (16),
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-- the requested extension is not supported by the TSA
addInfoNotAvailable (17),
-- the additional information requested could not be
-- understood or is not available
badSenderNonce (18),
-- not valid sender nonce, either missing or wrong size
badCertTemplate (19),
-- not valid cert. template or missing mandatory information
signerNotTrusted (20),
-- signer of the message unknown or not trusted
transactionIdInUse (21),
-- the transaction identifier is already in use
unsupportedVersion (22),
-- the version of the message is not supported
notAuthorized (23),
-- the sender was not authorized to make the preceding
-- request or perform the preceding action
systemUnavail (24),
-- the request cannot be handled due to system unavailability
systemFailure (25),
-- the request cannot be handled due to system failure
duplicateCertReq (26)
-- certificate cannot be issued because a duplicate
-- certificate already exists
}
PKIStatusInfo ::= SEQUENCE {
status PKIStatus,
statusString PKIFreeText OPTIONAL,
failInfo PKIFailureInfo OPTIONAL }
OOBCert ::= CMPCertificate
OOBCertHash ::= SEQUENCE {
hashAlg [0] AlgorithmIdentifier{DIGEST-ALGORITHM, {...}}
OPTIONAL,
certId [1] CertId OPTIONAL,
hashVal BIT STRING
-- hashVal is calculated over the DER encoding of the
-- self-signed certificate with the identifier certID.
}
POPODecKeyChallContent ::= SEQUENCE OF Challenge
-- One Challenge per encryption or key agreement key certification
-- request (in the same order as these requests appear in
-- CertReqMessages).
-- encryptedRand was added in [RFCXXXX]
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Challenge ::= SEQUENCE {
owf AlgorithmIdentifier{DIGEST-ALGORITHM, {...}}
OPTIONAL,
-- MUST be present in the first Challenge; MAY be omitted in
-- any subsequent Challenge in POPODecKeyChallContent (if
-- omitted, then the owf used in the immediately preceding
-- Challenge is to be used).
witness OCTET STRING,
-- the result of applying the one-way function (owf) to a
-- randomly-generated INTEGER, A. (Note that a different
-- INTEGER MUST be used for each Challenge.)
challenge OCTET STRING
-- MUST be used for cmp2000(2) popdecc messages and MUST be
-- the encryption of Rand (using a mechanism depending on the
-- private key type).
-- MUST be an empty OCTET STRING for cmp2021(3) popdecc messages.
-- Note: Using challenge omitting the optional encryptedRand is
-- bit-compatible to the syntax without adding this optional
-- field.
encryptedRand [0] EnvelopedData OPTIONAL
-- MUST be omitted for cmp2000(2) popdecc messages.
-- MUST be used for cmp2021(3) popdecc messages and MUST contain
-- the encrypted value of Rand using CMS EnvelopedData using the
-- key management technique depending on the private key type as
-- defined in Section 5.2.2.
}
-- Rand was added in [RFC9480]
Rand ::= SEQUENCE {
-- Rand is encrypted involving the public key to form the content of
-- challenge or encryptedRand in POPODecKeyChallContent
int INTEGER,
-- the randomly generated INTEGER A (above)
sender GeneralName
-- the sender's name (as included in PKIHeader)
}
POPODecKeyRespContent ::= SEQUENCE OF INTEGER
-- One INTEGER per encryption or key agreement key certification
-- request (in the same order as these requests appear in
-- CertReqMessages). The retrieved INTEGER A (above) is returned to
-- the sender of the corresponding Challenge.
CertRepMessage ::= SEQUENCE {
caPubs [1] SEQUENCE SIZE (1..MAX) OF CMPCertificate
OPTIONAL,
response SEQUENCE OF CertResponse }
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CertResponse ::= SEQUENCE {
certReqId INTEGER,
-- to match this response with the corresponding request (a value
-- of -1 is to be used if certReqId is not specified in the
-- corresponding request, which can only be a p10cr)
status PKIStatusInfo,
certifiedKeyPair CertifiedKeyPair OPTIONAL,
rspInfo OCTET STRING OPTIONAL
-- analogous to the id-regInfo-utf8Pairs string defined
-- for regInfo in CertReqMsg [RFC4211]
}
CertifiedKeyPair ::= SEQUENCE {
certOrEncCert CertOrEncCert,
privateKey [0] EncryptedKey OPTIONAL,
-- See [RFC4211] for comments on encoding.
-- Changed from EncryptedValue to EncryptedKey as a CHOICE of
-- EncryptedValue and EnvelopedData due to the changes made in
-- [RFC9480].
-- Using the choice EncryptedValue is bit-compatible to the
-- syntax without this change.
publicationInfo [1] PKIPublicationInfo OPTIONAL }
CertOrEncCert ::= CHOICE {
certificate [0] CMPCertificate,
encryptedCert [1] EncryptedKey
-- Changed from Encrypted Value to EncryptedKey as a CHOICE of
-- EncryptedValue and EnvelopedData due to the changes made in
-- [RFC9480].
-- Using the choice EncryptedValue is bit-compatible to the
-- syntax without this change.
}
KeyRecRepContent ::= SEQUENCE {
status PKIStatusInfo,
newSigCert [0] CMPCertificate OPTIONAL,
caCerts [1] SEQUENCE SIZE (1..MAX) OF
CMPCertificate OPTIONAL,
keyPairHist [2] SEQUENCE SIZE (1..MAX) OF
CertifiedKeyPair OPTIONAL }
RevReqContent ::= SEQUENCE OF RevDetails
RevDetails ::= SEQUENCE {
certDetails CertTemplate,
-- allows requester to specify as much as they can about
-- the cert. for which revocation is requested
-- (e.g., for cases in which serialNumber is not available)
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crlEntryDetails Extensions{{...}} OPTIONAL
-- requested crlEntryExtensions
}
RevRepContent ::= SEQUENCE {
status SEQUENCE SIZE (1..MAX) OF PKIStatusInfo,
-- in same order as was sent in RevReqContent
revCerts [0] SEQUENCE SIZE (1..MAX) OF CertId OPTIONAL,
-- IDs for which revocation was requested
-- (same order as status)
crls [1] SEQUENCE SIZE (1..MAX) OF CertificateList OPTIONAL
-- the resulting CRLs (there may be more than one)
}
CAKeyUpdAnnContent ::= SEQUENCE {
oldWithNew CMPCertificate, -- old pub signed with new priv
newWithOld CMPCertificate, -- new pub signed with old priv
newWithNew CMPCertificate -- new pub signed with new priv
}
CertAnnContent ::= CMPCertificate
RevAnnContent ::= SEQUENCE {
status PKIStatus,
certId CertId,
willBeRevokedAt GeneralizedTime,
badSinceDate GeneralizedTime,
crlDetails Extensions{{...}} OPTIONAL
-- extra CRL details (e.g., crl number, reason, location, etc.)
}
CRLAnnContent ::= SEQUENCE OF CertificateList
PKIConfirmContent ::= NULL
NestedMessageContent ::= PKIMessages
-- CertReqTemplateContent, AttributeTypeAndValue,
-- ExpandedRegControlSet, id-regCtrl-altCertTemplate,
-- AltCertTemplate, regCtrl-algId, id-regCtrl-algId, AlgIdCtrl,
-- regCtrl-rsaKeyLen, id-regCtrl-rsaKeyLen, and RsaKeyLenCtrl
-- were added in [RFC9480]
CertReqTemplateContent ::= SEQUENCE {
certTemplate CertTemplate,
-- prefilled certTemplate structure elements
-- The SubjectPublicKeyInfo field in the certTemplate MUST NOT
-- be used.
keySpec Controls OPTIONAL
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-- MAY be used to specify supported algorithms
-- Controls ::= SEQUENCE SIZE (1..MAX) OF AttributeTypeAndValue
-- as specified in CRMF [RFC4211]
}
AttributeTypeAndValue ::= SingleAttribute{{ ... }}
ExpandedRegControlSet ATTRIBUTE ::= { RegControlSet |
regCtrl-altCertTemplate | regCtrl-algId | regCtrl-rsaKeyLen, ... }
regCtrl-altCertTemplate ATTRIBUTE ::=
{ TYPE AltCertTemplate IDENTIFIED BY id-regCtrl-altCertTemplate }
id-regCtrl-altCertTemplate OBJECT IDENTIFIER ::= { id-regCtrl 7 }
AltCertTemplate ::= AttributeTypeAndValue
-- specifies a template for a certificate other than an X.509v3
-- public key certificate
regCtrl-algId ATTRIBUTE ::=
{ TYPE AlgIdCtrl IDENTIFIED BY id-regCtrl-algId }
id-regCtrl-algId OBJECT IDENTIFIER ::= { id-regCtrl 11 }
AlgIdCtrl ::= AlgorithmIdentifier{ALGORITHM, {...}}
-- SHALL be used to specify supported algorithms other than RSA
regCtrl-rsaKeyLen ATTRIBUTE ::=
{ TYPE RsaKeyLenCtrl IDENTIFIED BY id-regCtrl-rsaKeyLen }
id-regCtrl-rsaKeyLen OBJECT IDENTIFIER ::= { id-regCtrl 12 }
RsaKeyLenCtrl ::= INTEGER (1..MAX)
-- SHALL be used to specify supported RSA key lengths
-- RootCaKeyUpdateContent, CRLSource, and CRLStatus were added in
-- [RFC9480]
RootCaKeyUpdateContent ::= SEQUENCE {
newWithNew CMPCertificate,
-- new root CA certificate
newWithOld [0] CMPCertificate OPTIONAL,
-- X.509 certificate containing the new public root CA key
-- signed with the old private root CA key
oldWithNew [1] CMPCertificate OPTIONAL
-- X.509 certificate containing the old public root CA key
-- signed with the new private root CA key
}
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CRLSource ::= CHOICE {
dpn [0] DistributionPointName,
issuer [1] GeneralNames }
CRLStatus ::= SEQUENCE {
source CRLSource,
thisUpdate Time OPTIONAL }
-- KemCiphertextInfo and KemOtherInfo were added in [RFCXXXX]
KemCiphertextInfo ::= SEQUENCE {
kem AlgorithmIdentifier{KEM-ALGORITHM, {...}},
-- AlgId of the Key Encapsulation Mechanism algorithm
ct OCTET STRING
-- Ciphertext output from the Encapsulate function
}
KemOtherInfo ::= SEQUENCE {
staticString PKIFreeText,
-- MUST be "CMP-KEM"
transactionID OCTET STRING,
-- MUST contain the values from the message previously received
-- containing the ciphertext (ct) in KemCiphertextInfo
kemContext [0] OCTET STRING OPTIONAL
-- MAY contain additional algorithm specific context information
}
INFO-TYPE-AND-VALUE ::= TYPE-IDENTIFIER
InfoTypeAndValue ::= SEQUENCE {
infoType INFO-TYPE-AND-VALUE.
&id({SupportedInfoSet}),
infoValue INFO-TYPE-AND-VALUE.
&Type({SupportedInfoSet}{@infoType}) }
SupportedInfoSet INFO-TYPE-AND-VALUE ::= { ... }
-- Example InfoTypeAndValue contents include, but are not limited
-- to, the following (uncomment in this ASN.1 module and use as
-- appropriate for a given environment):
--
-- id-it-caProtEncCert OBJECT IDENTIFIER ::= {id-it 1}
-- CAProtEncCertValue ::= CMPCertificate
-- id-it-signKeyPairTypes OBJECT IDENTIFIER ::= {id-it 2}
-- SignKeyPairTypesValue ::= SEQUENCE SIZE (1..MAX) OF
-- AlgorithmIdentifier{{...}}
-- id-it-encKeyPairTypes OBJECT IDENTIFIER ::= {id-it 3}
-- EncKeyPairTypesValue ::= SEQUENCE SIZE (1..MAX) OF
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-- AlgorithmIdentifier{{...}}
-- id-it-preferredSymmAlg OBJECT IDENTIFIER ::= {id-it 4}
-- PreferredSymmAlgValue ::= AlgorithmIdentifier{{...}}
-- id-it-caKeyUpdateInfo OBJECT IDENTIFIER ::= {id-it 5}
-- CAKeyUpdateInfoValue ::= CAKeyUpdAnnContent
-- id-it-currentCRL OBJECT IDENTIFIER ::= {id-it 6}
-- CurrentCRLValue ::= CertificateList
-- id-it-unsupportedOIDs OBJECT IDENTIFIER ::= {id-it 7}
-- UnsupportedOIDsValue ::= SEQUENCE SIZE (1..MAX) OF
-- OBJECT IDENTIFIER
-- id-it-keyPairParamReq OBJECT IDENTIFIER ::= {id-it 10}
-- KeyPairParamReqValue ::= OBJECT IDENTIFIER
-- id-it-keyPairParamRep OBJECT IDENTIFIER ::= {id-it 11}
-- KeyPairParamRepValue ::= AlgorithmIdentifier{{...}}
-- id-it-revPassphrase OBJECT IDENTIFIER ::= {id-it 12}
-- RevPassphraseValue ::= EncryptedKey
-- - Changed from Encrypted Value to EncryptedKey as a CHOICE
-- - of EncryptedValue and EnvelopedData due to the changes
-- - made in [RFC9480]
-- - Using the choice EncryptedValue is bit-compatible to
-- - the syntax without this change
-- id-it-implicitConfirm OBJECT IDENTIFIER ::= {id-it 13}
-- ImplicitConfirmValue ::= NULL
-- id-it-confirmWaitTime OBJECT IDENTIFIER ::= {id-it 14}
-- ConfirmWaitTimeValue ::= GeneralizedTime
-- id-it-origPKIMessage OBJECT IDENTIFIER ::= {id-it 15}
-- OrigPKIMessageValue ::= PKIMessages
-- id-it-suppLangTags OBJECT IDENTIFIER ::= {id-it 16}
-- SuppLangTagsValue ::= SEQUENCE OF UTF8String
-- id-it-caCerts OBJECT IDENTIFIER ::= {id-it 17}
-- CaCertsValue ::= SEQUENCE SIZE (1..MAX) OF
-- CMPCertificate
-- - id-it-caCerts added in [RFC9480]
-- id-it-rootCaKeyUpdate OBJECT IDENTIFIER ::= {id-it 18}
-- RootCaKeyUpdateValue ::= RootCaKeyUpdateContent
-- - id-it-rootCaKeyUpdate added in [RFC9480]
-- id-it-certReqTemplate OBJECT IDENTIFIER ::= {id-it 19}
-- CertReqTemplateValue ::= CertReqTemplateContent
-- - id-it-certReqTemplate added in [RFC9480]
-- id-it-rootCaCert OBJECT IDENTIFIER ::= {id-it 20}
-- RootCaCertValue ::= CMPCertificate
-- - id-it-rootCaCert added in [RFC9480]
-- id-it-certProfile OBJECT IDENTIFIER ::= {id-it 21}
-- CertProfileValue ::= SEQUENCE SIZE (1..MAX) OF
-- UTF8String
-- - id-it-certProfile added in [RFC9480]
-- id-it-crlStatusList OBJECT IDENTIFIER ::= {id-it 22}
-- CRLStatusListValue ::= SEQUENCE SIZE (1..MAX) OF
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-- CRLStatus
-- - id-it-crlStatusList added in [RFC9480]
-- id-it-crls OBJECT IDENTIFIER ::= {id-it 23}
-- CRLsValue ::= SEQUENCE SIZE (1..MAX) OF
-- CertificateList
-- - id-it-crls added in [RFC9480]
-- id-it-KemCiphertextInfo OBJECT IDENTIFIER ::= {id-it TBD1}
-- KemCiphertextInfoValue ::= KemCiphertextInfo
-- - id-it-KemCiphertextInfo was added in [RFCXXXX]
--
-- where
--
-- id-pkix OBJECT IDENTIFIER ::= {
-- iso(1) identified-organization(3)
-- dod(6) internet(1) security(5) mechanisms(5) pkix(7)}
-- and
-- id-it OBJECT IDENTIFIER ::= {id-pkix 4}
--
--
-- This construct MAY also be used to define new PKIX Certificate
-- Management Protocol request and response messages or
-- general-purpose (e.g., announcement) messages for future needs
-- or for specific environments.
GenMsgContent ::= SEQUENCE OF InfoTypeAndValue
-- May be sent by EE, RA, or CA (depending on message content).
-- The OPTIONAL infoValue parameter of InfoTypeAndValue will
-- typically be omitted for some of the examples given above.
-- The receiver is free to ignore any contained OIDs that it
-- does not recognize. If sent from EE to CA, the empty set
-- indicates that the CA may send
-- any/all information that it wishes.
GenRepContent ::= SEQUENCE OF InfoTypeAndValue
-- The receiver MAY ignore any contained OIDs that it does not
-- recognize.
ErrorMsgContent ::= SEQUENCE {
pKIStatusInfo PKIStatusInfo,
errorCode INTEGER OPTIONAL,
-- implementation-specific error codes
errorDetails PKIFreeText OPTIONAL
-- implementation-specific error details
}
CertConfirmContent ::= SEQUENCE OF CertStatus
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CertStatus ::= SEQUENCE {
certHash OCTET STRING,
-- the hash of the certificate, using the same hash algorithm
-- as is used to create and verify the certificate signature
certReqId INTEGER,
-- to match this confirmation with the corresponding req/rep
statusInfo PKIStatusInfo OPTIONAL,
hashAlg [0] AlgorithmIdentifier{DIGEST-ALGORITHM, {...}} OPTIONAL
-- the hash algorithm to use for calculating certHash
-- SHOULD NOT be used in all cases where the AlgorithmIdentifier
-- of the certificate signature specifies a hash algorithm
}
PollReqContent ::= SEQUENCE OF SEQUENCE {
certReqId INTEGER }
PollRepContent ::= SEQUENCE OF SEQUENCE {
certReqId INTEGER,
checkAfter INTEGER, -- time in seconds
reason PKIFreeText OPTIONAL }
--
-- Extended key usage extension for PKI entities used in CMP
-- operations, added due to the changes made in [RFC9480]
-- The EKUs for the CA and RA are reused from CMC, as defined in
-- [RFC6402]
--
-- id-kp-cmcCA OBJECT IDENTIFIER ::= { id-kp 27 }
-- id-kp-cmcRA OBJECT IDENTIFIER ::= { id-kp 28 }
id-kp-cmKGA OBJECT IDENTIFIER ::= { id-kp 32 }
END
Appendix G. History of Changes
Note: This appendix will be deleted in the final version of the
document.
From version 07 -> 08:
* Aligned with released RFC 9480 - RFC 9483
* Updated Section 1.3
* Added text on usage of transactionID with KEM-bases message
protection to Section 5.1.1
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* Reverted a change to Section 5.1.3.1 from -02 and reinserting the
deleted text and adding some text explaining when a key expansion
is required.
* Consolidated the definition and transferal of KemCiphertextInfo.
Added a new Section 5.1.1.5 introducing KemCiphertextInfo in the
generalInfo filed and moving text on how to request a KEM
ciphertext using genm/genp from Section 5.1.3.4 to
Section 5.3.19.18
* Some editorial changes to Section 5.1.3.4 and Appendix E after
discussion with David resolving #30 and discussing at IETF 117.
Also introducing optional field kemContext to KemBasedMac and
KemOtherInfo as CMP-specific alternative to ukm in cms-kemri.
* Added ToDo for reviewing the reduced content of KemOtherInfo to
Section 5.1.3.4
* Added a cross-reference to Section 5.1.1.3 regarding use of
OrigPKIMessage to Section 5.1.3.5
* Added POP for KEM keys to Section 5.2.8. Restructured the section
and fixed some references which broke from RFC2510 to RFC4210.
Introduced a section on the usage of raVerified.
* Fixed the issue in Section 5.3.19.15, resulting from a change made
in draft-ietf-lamps-cmp-updates-14, that no plain public-key can
be used in the request message in CMPCertificate.
* Updated Appendix B regarding KEM-based message protection and
usage of CMS EnvelopedData
From version 06 -> 07:
* Updated section 5.1.1.4 addressing a question from Liao Lijun on
how to interpret less profile names than certReqMsgs
* Updated section 5.1.3.4 specifying establishing a shares secret
key for one arbitrary side of the CMP communication only
* Removed the note and the security consideration regarding combiner
function for HPKE
* Added security considerations 8.1 and 8.8
* Updates IANA Considerations in section 9 to add new OID for the
updates ASN.1 module and for id-it-KemCiphertextInfo
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* Added new appendix E showing different variants of using KEM keys
for PKI message protection
* Updates ASN.1 module in appendix F
From version 05 -> 06:
* Updated section 5.1.3.4 exchanging HPKE with plain KEM+KDF as also
used in draft-ietf-lamps-cms-kemri
From version 04 -> 05:
* Updated sections 5.1.3.4, 5.2.2, and 8.9 addressing comments from
Russ (see thread "I-D Action: draft-ietf-lamps-rfc4210bis-04.txt")
From version 03 -> 04:
* Added Section 4.3.4 regarding POP for KEM keys
* Added Section 5.1.3.4 on message protection using KEM keys and
HPKE
* Aligned Section 5.2.2 on guidance which CMS key management
technique to use with encrypted values (see thread "CMS: selection
of key management technique to use for EnvelopedData") also adding
support for KEM keys
* Added Section 8.9 and extended Section 3.1.2 regarding use of
Certificate Transparency logs
* Deleted former Appendix C as announced in the -03
* Fixed some nits resulting from XML -> MD conversion
From version 02 -> 03:
* Updated Section 4.4.1 clarifying the definition of "new with new"
certificate validity period (see thread "RFC4210bis - notAfter
time of newWithNew certificate")
* Added ToDo to Section 4.3 and 5.2.8 on required alignment
regarding POP for KEM keys.
* Updated Sections 5.2.1, 5.2.8, and 5.2.8.1 incorporating text of
former Appendix C (see thread "draft-ietf-lamps-rfc4210bis - ToDo
on review of Appendix C")
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* Added a ToDo to Appendix B to indicate additional review need to
try pushing the content to Sections 4 and Section 5
From version 01 -> 02:
* Added Section 3.1.1.4 introducing the Key Generation Authority
* Added Section 5.1.1.3 containing description of origPKIMessage
content moved here from Section 5.1.3.4
* Added ToDos on defining POP and message protection using KEM keys
* Added a ToDo to Section 4.4.3
* Added a ToDo to Appendix C to do a more detailed review
* Removed concrete algorithms and referred to CMP Algorithms instead
* Added references to Appendix D and E as well as the Lightweight
CMP Profile for further information
* Broaden the scope from human users also to devices and services
* Addressed idnits feedback, specifically changing from historic
LDAP V2 to LDAP V3 (RFC4511)
* Did some further editorial alignment to the XML
From version 00 -> 01:
* Performed all updates specified in CMP Updates Section 2 and
Appendix A.2.
* Did some editorial alignment to the XML
Version 00:
This version consists of the text of RFC4210 with the following
changes:
* Introduced the authors of this document and thanked the authors of
RFC4210 for their work.
* Added a paragraph to the introduction explaining the background of
this document.
* Added the change history to this appendix.
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Authors' Addresses
Hendrik Brockhaus
Siemens
Werner-von-Siemens-Strasse 1
80333 Munich
Germany
Email: hendrik.brockhaus@siemens.com
URI: https://www.siemens.com
David von Oheimb
Siemens
Werner-von-Siemens-Strasse 1
80333 Munich
Germany
Email: david.von.oheimb@siemens.com
URI: https://www.siemens.com
Mike Ounsworth
Entrust
1187 Park Place
Minneapolis, MN 55379
United States of America
Email: mike.ounsworth@entrust.com
URI: https://www.entrust.com
John Gray
Entrust
1187 Park Place
Minneapolis, MN 55379
United States of America
Email: john.gray@entrust.com
URI: https://www.entrust.com
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