| Internet-Draft | RPKI Signed Checklist | February 2022 |
| Snijders, et al. | Expires 16 August 2022 | [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 an arbitrary checksum listing with a specific 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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Copyright (c) 2022 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 a specific set of Internet Number Resources.¶
Signed Checklists are expected to facilitate inter-domain business use-cases which depend on an ability to verify resource holdership. RPKI-based validation processes are expected to become the industry norm for automated Bring Your Own IP (BYOIP) on-boarding or establishment of physical interconnection between Autonomous Systems.¶
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 the RTA profile allows multiple signers to attest a single digital object through a checksum of its content, while the RSC profile allows a single signer to attest the existence of multiple digital objects. A single signer profile is considered a simplification for both 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 MUST be omitted from the RSC's X.509 End-Entity (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 CA MUST only sign one RSC with each EE Certificate, and MUST generate a new key pair for each new RSC. This form of use of the associated EE Certificate is termed a "one-time-use" EE certificate Section 3 of [RFC6487].¶
The ContentType for an RSC is defined as rpkiSignedChecklist, and has the numerical value of 1.2.840.113549.1.9.16.1.48.¶
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 a checklist for arbitrary 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-2010 -- in [RFC6268]
{ iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
pkcs-9(9) smime(16) modules(0) id-mod-cms-2009(58) }
ASIdOrRange, IPAddressOrRange
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) 48 }
RpkiSignedChecklist ::= SEQUENCE {
version [0] INTEGER DEFAULT 0,
resources ResourceBlock,
digestAlgorithm DigestAlgorithmIdentifier,
checkList SEQUENCE SIZE (1..MAX) OF FileNameAndHash }
FileNameAndHash ::= SEQUENCE {
fileName IA5String OPTIONAL,
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 IPAddressFamilyItem
IPAddressFamilyItem ::= SEQUENCE { -- AFI & optional SAFI --
addressFamily OCTET STRING (SIZE (2..3)),
iPAddressOrRange IPAddressOrRange }
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 FileNameAndHash objects. There is one FileNameAndHash entry for each arbitrary object referenced on the Signed Checklist. Each FileNameAndHash is an ordered pair of the name of the directory entry containing the digital object and the message digest of the digital object. The filename field is OPTIONAL.¶
Before a Relying Party can use an RSC to validate a set of digital objects, the Relying Party MUST first validate the RSC. To validate an RSC, the Relying Party MUST perform all the validation checks specified in [RFC6488] (except checking for the presence of a SIA extension), and perform the following additional RSC-specific validation steps:¶
To verify a set of digital objects with an RSC:¶
When creating digital objects of a plain-text nature (such as ASCII, UTF-8, HTML, Javascript, XML, etc) it is RECOMMENDED to convert such objects into a lossless compressed form. Distributing plain-text objects within a compression envelope (such as GZIP [RFC1952]) might help avoid unexpected canonicalization at intermediate systems (which in turn would lead to checksum verification errors). Validator implementations are expected to treat a checksummed digital object as string of arbitrary single octets.¶
If a filename field is present, but no referenced digital object has a filename that matches the content of that field, a validator implementation SHOULD compare the message digest of each digital object to the value from the messageDigest field of the associated FileNameAndHash, and report matches to the client for further consideration.¶
Relying parties are hereby warned that the data in a RPKI Signed Checklist is self-asserted. When determining the meaning of any data contained in an RPKI Signed Checklist, Relying Parties MUST NOT make any assumptions about the signer beyond the fact that it had sufficient control of the issuing CA to create the object. These data have not been verified by the Certificate Authority (CA) that issued the CA certificate to the entity that issued the EE Certificate used to validate the Signed Checklist.¶
RPKI Certificates are not bound to real world identities, see [I-D.ymbk-sidrops-rpki-has-no-identity] for an elaboration. Relying Parties can only associate real world entities to Internet Number Resources by additionally consulting an exogenous authority. Signed Checklists are a tool to communicate assertions 'signed with Internet Number Resources', not about any other aspect of the resource holder's business operations such as the identity of the resource holder itself.¶
RSC objects are not distributed through the RPKI Repository system. From this, it follows that third parties who do not have a copy of a given RSC, may not be aware of the existence of that RSC. Since RSC objects use EE Certificates, but all other currently defined types of RPKI object profiles are published in public CA repositories, an observer may infer from discrepancies in the Repository that RSC object(s) may exist. For example, if a CA does not use random serial numbers for Certificates, an observer could detect gaps between the serial numbers of the published EE Certificates. Similarly, if the CA includes a serial number on a CRL that does not match any published object, an observer could postulate an RSC EE Certificate was revoked.¶
Conversely, a gap in serial numbers does not imply that an RSC exists. Nor does an arbitrary (to the RP unknown) serial in a CRL imply an RSC object exists: the implicitly referenced object might not be a RSC, it might never have been published, or was revoked before it was visible to RPs. In general, it is not possible to confidently infer the existence or non-existence of RSCs from the Repository state without access to a given RSC.¶
While an one-time-use EE Certificate must only be used to generate and sign a single RSC object, CAs technically are not restricted from generating and signing multiple different RSC objects with a single keypair. Any RSC objects sharing the same EE Certificate can not be revoked individually.¶
This section is to be removed before publishing as an RFC.¶
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 permanently allocated for this document in the SMI Security for S/MIME CMS Content Type (1.2.840.113549.1.9.16.1) registry:¶
Decimal Description References --------------------------------------------------------------- 48 id-ct-signedChecklist [draft-ietf-sidrops-rpki-rsc]¶
Upon publication of this document, IANA is requested to reference the RFC publication instead of this draft.¶
The IANA is requested to register the OID for the RPKI Signed Checklist in the registry created by [RFC6488] as following:¶
Name OID Specification ------------------------------------------------------------- Signed Checklist 1.2.840.113549.1.9.16.1.48 [draft-ietf-sidrops-rpki-rsc]¶
The IANA is requested to add an item for the Signed Checklist file extension to the "RPKI Repository Name Scheme" registry created by [RFC6481] as follows:¶
Filename Extension RPKI Object Reference
-------------------------------------------------------------------
.sig Signed Checklist [draft-ietf-sidrops-rpki-rsc]
¶
The IANA is requested to add an item to the "SMI Security for S/MIME Module Identifier" registry as follows:¶
Decimal Description References
-----------------------------------------------------------------------
TBD id-mod-rpkiSignedChecklist-2021 [draft-ietf-sidrops-rpki-rsc]
¶
The IANA is requested to register the media type application/rpki-checklist in the Provisional Standard Media Type registry 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 authors wish 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 authors thank Russ Housley for reviewing the ASN.1 notation and providing suggestions. The authors would like to thank Nimrod Levy, Tim Bruijnzeels, Alberto Leiva, Ties de Kock, and Peter Peele for document review and suggestions.¶
This section is to be removed before publishing as an RFC.¶