| Internet-Draft | RPKI Signed Checklists | February 2021 |
| Snijders | Expires 19 August 2021 | [Page] |
This document defines a Cryptographic Message Syntax (CMS) profile for a general purpose listing of checksums (a 'checklist'), for use with the Resource Public Key Infrastructure (RPKI). The objective is to allow an attestation, in the form of a listing of one or more checksums of arbitrary digital objects (files), to be signed "with resources", and for validation to provide a means to confirm a specific Internet Resource Holder produced the signed checklist. The profile is intended to provide for the signing of a checksum listing with an arbitrary set of Internet Number Resources.¶
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.¶
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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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This Internet-Draft will expire on 19 August 2021.¶
Copyright (c) 2021 IETF Trust and the persons identified as the document authors. All rights reserved.¶
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This document defines a Cryptographic Message Syntax (CMS) [RFC5652] profile for a general purpose listing of checksums (a 'checklist'), for use with the Resource Public Key Infrastructure (RPKI) [RFC6480]. The objective is to allow an attestation, in the form of a listing of one or more checksums of arbitrary files, to be signed "with resources", and for validation to provide a means to confirm a given Internet Resource Holder produced the RPKI Signed Checklist (RSC). The profile is intended to provide for the signing of a checksum listing with an arbitrary set of Internet Number Resources.¶
RSC files are expected to facilitate Bring Your Own IP (BYOIP) authentication, inter-domain interconnection provisioning, and resource holdership verification processes.¶
The RSC concept borrows heavily from RTA [I-D.ietf-sidrops-rpki-rta], Manifests [RFC6486], and OpenBSD's [signify] utility. The main difference between RSC and RTA is that an RTA enables multiple signers to attest a single anonymous digital object through a checksum of its content, while an RSC allows a single signer to attest the checksums of multiple named digital objects. This difference is expected to represent a simplification for implementers and operators.¶
RSC follows the Signed Object Template for the RPKI [RFC6488] with one exception. Because RSCs MUST NOT be distributed through the global RPKI repository system, the Subject Information Access (SIA) extension is omitted from the RSC's X.509 EE certificate.¶
What constitutes suitable transport for RSC files is deliberately unspecified. It might be a USB stick, a web interface secured with conventional HTTPS, PGP-signed email, a T-shirt printed with a QR code, or a carrier pigeon.¶
The ContentType for an RSC is defined as rpkiSignedChecklist, and has the numerical value of 1.2.840.113549.1.9.16.1.TBD.¶
This OID MUST appear both within the eContentType in the encapContentInfo object as well as the ContentType signed attribute in the signerInfo object (see [RFC6488]).¶
The content of an RSC indicates that an a checklist for arbitrary named digital objects has been signed "with resources". An RSC is formally defined as:¶
RpkiSignedChecklist-2021
{ iso(1) member-body(2) us(840) rsadsi(113549)
pkcs(1) pkcs9(9) smime(16) mod(0) TBD }
DEFINITIONS EXPLICIT TAGS ::=
BEGIN
IMPORTS
CONTENT-TYPE, Digest, DigestAlgorithmIdentifier
FROM CryptographicMessageSyntax-2009 -- in [RFC5911]
{ iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
pkcs-9(9) smime(16) modules(0) id-mod-cms-2004-02(41) }
ASIdOrRange, IPAddressFamily
FROM IPAddrAndASCertExtn -- in [RFC3779]
{ iso(1) identified-organization(3) dod(6) internet(1)
security(5) mechanisms(5) pkix(7) mod(0)
id-mod-ip-addr-and-as-ident(30) } ;
ct-rpkiSignedChecklist CONTENT-TYPE ::=
{ TYPE RpkiSignedChecklist IDENTIFIED BY
id-ct-signedChecklist }
id-ct-signedChecklist OBJECT IDENTIFIER ::=
{ iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
pkcs-9(9) id-smime(16) id-ct(1) TBD }
RpkiSignedChecklist ::= SEQUENCE {
version [0] INTEGER DEFAULT 0,
resources ResourceBlock,
digestAlgorithm DigestAlgorithmIdentifier,
checkList SEQUENCE SIZE (1..MAX) OF FileAndHash }
FileAndHash ::= SEQUENCE {
file IA5String,
hash Digest }
ResourceBlock ::= SEQUENCE {
asID [0] AsList OPTIONAL,
ipAddrBlocks [1] IPList OPTIONAL }
-- at least one of asID or ipAddrBlocks MUST be present
( WITH COMPONENTS { ..., asID PRESENT} |
WITH COMPONENTS { ..., ipAddrBlocks PRESENT } )
AsList ::= SEQUENCE (SIZE(1..MAX)) OF ASIdOrRange
IPList ::= SEQUENCE (SIZE(1..MAX)) OF IPAddressFamily
END
¶
The version number of the RpkiSignedChecklist MUST be 0.¶
The resources contained here are the resources used to mark the attestation, and MUST match the set of resources listed by the EE certificate carried in the CMS certificates field.¶
The digest algorithm used to create the message digest of the attested digital object. This algorithm MUST be a hashing algorithm defined in [RFC7935].¶
This field is a sequence of FileAndHash objects. There is one FileAndHash entry for each arbitrary object referenced from the RSC. Each FileAndHash is an ordered pair consisting of the name of the file that contains the object in question and a hash of the file's contents.¶
When working with objects of a plain-text nature (ASCII, UTF-8, HTML, Javascript, XML, etc) it is RECOMMENDED to distribute such objects in a lossless compressed form, and sign the compressed form. Wrapping plain-text objects in a compression envelope can help make those appear as a single octet string to any intermediate systems, which hopefully discourages in-transit modification of the file contents. The use of lossless compression can help avoid checksum verification errors.¶
To validate an RSC the relying party MUST perform all the validation checks specified in [RFC6488] as well as the following additional RSC-specific validation steps.¶
Relying parties are hereby warned that the data in a RPKI Signed Checklist is self-asserted. These data have not been verified by the CA that issued the CA certificate to the entity that issued the EE certificate used to validate the Signed Checklist.¶
This section records the status of known implementations of the protocol defined by this specification at the time of posting of this Internet-Draft, and is based on a proposal described in RFC 7942. The description of implementations in this section is intended to assist the IETF in its decision processes in progressing drafts to RFCs. Please note that the listing of any individual implementation here does not imply endorsement by the IETF. Furthermore, no effort has been spent to verify the information presented here that was supplied by IETF contributors. This is not intended as, and must not be construed to be, a catalog of available implementations or their features. Readers are advised to note that other implementations may exist.¶
According to RFC 7942, "this will allow reviewers and working groups to assign due consideration to documents that have the benefit of running code, which may serve as evidence of valuable experimentation and feedback that have made the implemented protocols more mature. It is up to the individual working groups to use this information as they see fit".¶
The IANA has registered the OID for the RPKI Signed Checklist in the registry created by [RFC6488] as follows:¶
Name OID Specification --------------------------------------------------------- Checklists 1.2.840.113549.1.9.16.1.TBD [RFC-TBD]¶
The IANA has added an item for the signed Checklist file extension to the "RPKI Repository Name Scheme" created by [RFC6481] as follows:¶
Filename Extension RPKI Object Reference
-----------------------------------------------------------
.sig Signed Checklist [RFC-TBD]
¶
The IANA has registered the media type application/rpki-checklist as follows:¶
Type name: application
Subtype name: rpki-checklist
Required parameters: None
Optional parameters: None
Encoding considerations: binary
Security considerations: Carries an RPKI Signed Checklist
[RFC-TBD].
Interoperability considerations: None
Published specification: This document.
Applications that use this media type: RPKI operators.
Additional information:
Content: This media type is a signed object, as defined
in [RFC6488], which contains a payload of a list of
checksums as defined above in this document.
Magic number(s): None
File extension(s): .sig
Macintosh file type code(s):
Person & email address to contact for further information:
Job Snijders <job@fastly.com>
Intended usage: COMMON
Restrictions on usage: None
Author: Job Snijders <job@fastly.com>
Change controller: Job Snijders <job@fastly.com>
¶
The author wishes to thank George Michaelson, Tom Harrison, Geoff Huston, Randy Bush, Stephen Kent, Matt Lepinski, Rob Austein, Ted Unangst, and Marc Espie for prior art. The author thanks Russ Housley for reviewing the ASN.1 notation and providing suggestions. The author would like to thank Nimrod Levy and Tom Harrison for document review and suggestions.¶