Internet DRAFT - draft-turner-lamps-nist-pqc-kem-certificates
draft-turner-lamps-nist-pqc-kem-certificates
None S. Turner
Internet-Draft sn3rd
Intended status: Standards Track P. Kampanakis
Expires: 8 September 2022 J. Massimo
AWS
B. Westerbaan
Cloudflare
7 March 2022
Algorithm Identifiers for NIST's PQC Algorithms for Use in the Internet
X.509 Public Key Infrastructure
draft-turner-lamps-nist-pqc-kem-certificates-01
Abstract
This document specifies algorithm identifiers and ASN.1 encoding
format for the US NIST's PQC KEM (United States National Institute of
Standards and Technology's Post Quantum Cryptography Key
Encapsulation Mechanism) algorithms. The algorithms covered are
Candidate TBD1. The encoding for public key and private key is also
provided.
[EDNOTE: This draft is not expected to be finalized before the NIST
PQC Project has standardized PQ algorithms. After NIST has
standardized its first algorithms, this document will replace TBD,
with the appropriate algorithms and parameters before proceeding to
ratification. The algorithm Candidate TBD1 has been added as an
example in this draft, to provide a more detailed illustration of the
content - it by no means indicates its inclusion in the final
version. This specification will use object identifiers for the new
algorithms that are assigned by NIST, and will use placeholders until
these are released.]
About This Document
This note is to be removed before publishing as an RFC.
Status information for this document may be found at
https://datatracker.ietf.org/doc/draft-turner-lamps-nist-pqc-kem-
certificates/.
Discussion of this document takes place on the Limited Additional
Mechanisms for PKIX and SMIME (lamps) Working Group mailing list
(mailto:spasm@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/browse/spasm/.
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Source for this draft and an issue tracker can be found at
https://github.com/ seanturner/draft-turner-lamps-nist-pqc-kem-
certificates.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 8 September 2022.
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
3. Algorithm Identifiers . . . . . . . . . . . . . . . . . . . . 3
4. Candidate TBD1 . . . . . . . . . . . . . . . . . . . . . . . 4
5. Subject Public Key Fields . . . . . . . . . . . . . . . . . . 4
6. Key Usage Bits . . . . . . . . . . . . . . . . . . . . . . . 5
7. Private Key Format . . . . . . . . . . . . . . . . . . . . . 5
8. ASN.1 Module . . . . . . . . . . . . . . . . . . . . . . . . 6
9. Security Considerations . . . . . . . . . . . . . . . . . . . 6
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
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11.1. Normative References . . . . . . . . . . . . . . . . . . 7
11.2. Informative References . . . . . . . . . . . . . . . . . 7
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
The US NIST PQC Project has selected the Candidate TBD1 algorithms as
winners of their PQC Project [PQCProj]. These algorithms are KEM
algorithms. NIST has also defined object identifiers for these
algorithms (TODO insert reference).
This document specifies the use of the Candidate TBD1 algorithms in
X.509 public key certifiates, see [RFC5280]. It also specifies
private key encoding. An ASN.1 module is included for reference
purposes.
These certificates could be used as Issuers in CMS where the public
key is used to encapsulate a shared secret used to derive a symmetric
key used to encrypt content in CMS [EDNOTE: Add reference draft-
perret-prat-lamps-cms-pq-kem]. To be used in TLS, these certificates
could only be used as end-entity identity certificates and would
require significant updates to the protocol [EDNOTE: Add reference
draft-celi-wiggers-tls-authkem].
2. Conventions and Definitions
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. Algorithm Identifiers
Certificates conforming to [RFC5280] can convey a public key for any
public key algorithm. The certificate indicates the algorithm
through an algorithm identifier. An algorithm identifier consists of
an object identifier and optional parameters.
The AlgorithmIdentifier type, which is included herein for
convenience, is defined as follows:
AlgorithmIdentifier ::= SEQUENCE {
algorithm OBJECT IDENTIFIER,
parameters ANY DEFINED BY algorithm OPTIONAL
}
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| NOTE: The above syntax is from [RFC5280] and matches the
| version used therein, i.e., the 1988 ASN.1 syntax. See
| [RFC5912] for ASN.1 copmatible with the 2015 ASN.1 syntax.
The fields in AlgorithmIdentifier have the following meanings:
* algorithm identifies the cryptographic algorithm with an object
identifier. XXX such OIDs are defined in Sections Section 4.
* parameters, which are optional, are the associated parameters for
the algorithm identifier in the algorithm field.
In this document, TODO (specify number) new OIDs for identifying the
different algorithm and parameter pairs. For all of the object
identifiers, the parameters MUST be absent.
It is possible to find systems that require the parameters to be
present. This can be due to either a defect in the original 1997
syntax or a programming error where developers never got input where
this was not true. The optimal solution is to fix these systems;
where this is not possible, the problem needs to be restricted to
that subsystem and not propagated to the Internet.
4. Candidate TBD1
TODO insert object-identifiers
5. Subject Public Key Fields
In the X.509 certificate, the subjectPublicKeyInfo field has the
SubjectPublicKeyInfo type, which has the following ASN.1 syntax:
SubjectPublicKeyInfo ::= SEQUENCE {
algorithm AlgorithmIdentifier,
subjectPublicKey BIT STRING
}
| NOTE: The above syntax is from [RFC5280] and matches the
| version used therein, i.e., the 1988 ASN.1 syntax. See
| [RFC5912] for ASN.1 copmatible with the 2015 ASN.1 syntax.
The fields in SubjectPublicKeyInfo have the following meanings:
* algorithm is the algorithm identifier and parameters for the
public key (see above).
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* subjectPublicKey contains the byte stream of the public key. The
algorithms defined in this document always encode the public key
as TODO pick format e.g., exact multiple of 8 bits?.
The following is an example of a TBD public key encoded using the
textual encoding defined in [RFC7468].
-----BEGIN PUBLIC KEY-----
TODO insert example public key
-----END PUBLIC KEY-------
6. Key Usage Bits
The intended application for the key is indicated in the keyUsage
certificate extension; see Section 4.2.1.3 of [RFC5280].
If the keyUsage extension is present in a certificate that indicates
Candidate TBD1 in SubjectPublicKeyInfo, then the following MUST be
present:
keyEncipherment;
7. Private Key Format
"Asymmetric Key Packages" [RFC5958] describes how to encode a private
key in a structure that both identifies what algorithm the private
key is for and allows for the public key and additional attributes
about the key to be included as well. For illustration, the ASN.1
structure OneAsymmetricKey is replicated below. The algorithm-
specific details of how a private key is encoded are left for the
document describing the algorithm itself.
OneAsymmetricKey ::= SEQUENCE {
version Version,
privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
privateKey PrivateKey,
attributes [0] IMPLICIT Attributes OPTIONAL,
...,
[[2: publicKey [1] IMPLICIT PublicKey OPTIONAL ]],
...
}
PrivateKey ::= OCTET STRING
PublicKey ::= BIT STRING
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| NOTE: The above syntax is from [RFC5958] and matches the
| version used therein, i.e., the 2002 ASN.1 syntax. The syntax
| used therein is compatible with the 2015 ASN.1 syntax.
For the keys defined in this document, the private key is always an
opaque byte sequence. The ASN.1 type PqckemPrivateKey is defined in
this document to hold the byte sequence. Thus, when encoding a
OneAsymmetricKey object, the private key is wrapped in a
PqckemPrivateKey object and wrapped by the OCTET STRING of the
"privateKey" field.
PqckemPrivateKey ::= OCTET STRING
The following is an example of a TBD private key encoded using the
textual encoding defined in [RFC7468].
-----BEGIN PRIVATE KEY-----
TODO iser example private key
-----END PRIVATE KEY-------
The following example, in addition to encoding the TBD private key,
has an attribute included as well as the public key. As with the
prior example, the textual encoding defined in [RFC7468] is used.
-----BEGIN PRIVATE KEY-----
TODO insert example private key with attribute
-----END PRIVATE KEY-------
| NOTE: There exist some private key import functions that have
| not implemented the new ASN.1 structure OneAsymmetricKey that
| is defined in [RFC5958]. This means that they will not accept
| a private key structure that contains the public key field.
| This means a balancing act needs to be done between being able
| to do a consistency check on the key pair and widest ability to
| import the key.
8. ASN.1 Module
TODO ASN.1 Module
9. Security Considerations
The Security Considerations section of [RFC5280] applies to this
specification as well.
[EDNOTE: Discuss side-channels for Candidate TBD1.]
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10. IANA Considerations
This document will have some IANA actions.
11. References
11.1. Normative References
[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/info/rfc2119>.
[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/info/rfc5280>.
[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/info/rfc5912>.
[RFC5958] Turner, S., "Asymmetric Key Packages", RFC 5958,
DOI 10.17487/RFC5958, August 2010,
<https://www.rfc-editor.org/info/rfc5958>.
[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/info/rfc8174>.
11.2. Informative References
[PQCProj] National Insititue of Standards and Technology, "Post-
Quantum Cryptography Project", 20 December 2016,
<https://csrc.nist.gov/projects/post-quantum-
cryptography>.
[RFC7468] Josefsson, S. and S. Leonard, "Textual Encodings of PKIX,
PKCS, and CMS Structures", RFC 7468, DOI 10.17487/RFC7468,
April 2015, <https://www.rfc-editor.org/info/rfc7468>.
Acknowledgments
TODO acknowledge.
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Authors' Addresses
Sean Turner
sn3rd
Email: sean@sn3rd.com
Panos Kampanakis
AWS
Email: kpanos@amazon.com
Jake Massimo
AWS
Email: jakemas@amazon.com
Bas Westerbaan
Cloudflare
Email: bas@westerbaan.name
Turner, et al. Expires 8 September 2022 [Page 8]
