Network Working Group J. Preuß Mattsson Internet-Draft G. Selander Intended status: Standards Track Ericsson AB Expires: 6 November 2025 S. Raza J. Höglund RISE AB M. Furuhed Nexus Group 5 May 2025 CBOR Encoded Certificate Revocation Management draft-cose-cbor-revocation-management-latest Abstract This document specifies CBOR encodings of messages for certificate revocation lists, and 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-cose-cbor-revocation- management/. Discussion of this document takes place on the CBOR Object Signing and Encryption Working Group mailing list (mailto:cose@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/cose/. Subscribe at https://www.ietf.org/mailman/listinfo/cose/. Source for this draft and an issue tracker can be found at https://github.com/cose-wg/CBOR-certificates. 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Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction 2. Notational Conventions 3. C509 Certificate Revocation List 4. C509 Online Certificate Status Protocol 4.1. C509 OCSP request 4.2. C509 OCSP response 5. Example C509 CRL Message 6. Example C509 OCSP Message Acknowledgments Normative References Authors' Addresses 1. Introduction One of the challenges with deploying a Public Key Infrastructure (PKI) for the Internet of Things (IoT) is the management of X.509 public key certificates [RFC5280], since that is not optimized for constrained environments with restricted hardware definitions and data transport capabilities, see [RFC7228]. A more compact representation of X.509 certificates has been specified through the use of the Concise Binary Object Representation (CBOR, [RFC8949]). This CBOR encoding of X.509 certificates, referred to as C509 [I-D.ietf-cose-cbor-encoded-cert], also enables reduced code complexity, code size, memory and CPU usage, while allowing compatibility with ordinary ASN.1 DER-encoded X.509 for use with legacy deployments. A "native" C509 encoding is specified, identical to the backwards compatible format except for the scope of the signature, suitable for very constrained greenfield deployments. The current specification adds to this work by specifying corresponding revokation related encoding and strucure. 2. Notational Conventions 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. This specification makes use of the terminology in [RFC5280], and [RFC6960]. When referring to CBOR, this specification always refers to Deterministically Encoded CBOR as specified in Sections 4.2.1 and 4.2.2 of [RFC8949]. 3. C509 Certificate Revocation List The section defines the C509 Certificate Revocation List (CRL) format based on and compatible with [RFC5280] reusing the formatting for C509 certificates defined in [I-D.ietf-cose-cbor-encoded-cert]. C509CertificateRevocationList = [ TBSCertificateRevocationList, issuerSignatureValue : any, ] ; The elements of the following group are used in a CBOR Sequence: TBSCertificateRevocationList = ( C509CertificateRevocationListType: int, issuer: Name, thisUpdate: Time, nextUpdate: Time, revokedCertificates: RevokedCertificates, crlExtensions: Extensions, issuerSignatureAlgorithm: AlgorithmIdentifier, ) RevokedCertificates = [ userCertificate: CertificateSerialNumber, revocationDate: Time, crlEntryExtensions: Extensions, ] Figure 1: CDDL for C509CertificateRevocationList. 4. C509 Online Certificate Status Protocol 4.1. C509 OCSP request To encode OCSP requests, the CDDL below gives the cbor encoding corresponding to the ASN.1 encoding defined in RFC 6960 [RFC6960]. C509OCSPRequest = [ TBSRequest, optionalSignature : *any, ] TBSRequest = [ version : uint .default 1, requestorName : *GeneralName, requestList : [+Request], requestExtensions : *[+extension] ] Request = [ reqCert : CertID, singleRequestExtensions : *[+extension] ] CertID = [ hashAlgorithm : AlgorithmIdentifier, issuerNameHash : bytes, -- Hash of issuer's DN issuerKeyHash : bytes, -- Hash of issuer's public key serialNumber : CertificateSerialNumber ] extension = TBD IMPORTS GeneralName, AlgorithmIdentifier, CertificateSerialNumber FROM Main C509 document Figure 2: CDDL for C509OCSPRequest. 4.2. C509 OCSP response Concerning OCSP responses we address the id-pkix-ocsp-basic response type as defined in defined in RFC 6960 [RFC6960]. C509OCSPResponse = [ responseStatus : C509OCSPResponseStatus, responseBytes : *BasicOCSPResponse ] OCSPResponseStatus = 0..6 ; inclusive range ; semantics of integer values as in rfc6960, 4.2.1. ASN.1 Specification of the OCSP Response BasicOCSPResponse = [ tbsResponseData : ResponseData, signatureAlgorithm : AlgorithmIdentifier, signature : any, certs : *[C509Certificate] ] ResponseData = [ version : uint .default 1, responderID : ResponderID, producedAt : Time, responses : [+SingleResponse], responseExtensions : *[+extension] ResponderID = Name / KeyHash Name = TBD KeyHash = bytes -- SHA-1 hash of responder's public key (excluding the tag and length fields) ; OBSOLETE, but needed if we want to fully recreate RFC6960 style messages SingleResponse = [ certID : CertID, certStatus : CertStatus, thisUpdate : Time, nextUpdate : *Time, singleExtensions : *[+extension] ] CertStatus = {1: NULL} / {2: RevokedInfo} / {3: NULL} ; good / revoked / unknown, semantics from RFC6960 RevokedInfo = ( revocationTime : Time, revocationReason : *CRLReason ) CRLReason = 0..10 ; inclusive range ; semantics of integer values from RFC6960, 5.3.1. Figure 3: CDDL for C509OCSPResponse. 5. Example C509 CRL Message TODO 6. Example C509 OCSP Message TODO Acknowledgments TODO Normative References [I-D.ietf-cose-cbor-encoded-cert] Mattsson, J. P., Selander, G., Raza, S., Höglund, J., and M. Furuhed, "CBOR Encoded X.509 Certificates (C509 Certificates)", Work in Progress, Internet-Draft, draft- ietf-cose-cbor-encoded-cert-13, 3 March 2025, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [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, . [RFC6960] Santesson, S., Myers, M., Ankney, R., Malpani, A., Galperin, S., and C. Adams, "X.509 Internet Public Key Infrastructure Online Certificate Status Protocol - OCSP", RFC 6960, DOI 10.17487/RFC6960, June 2013, . [RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for Constrained-Node Networks", RFC 7228, DOI 10.17487/RFC7228, May 2014, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8949] Bormann, C. and P. Hoffman, "Concise Binary Object Representation (CBOR)", STD 94, RFC 8949, DOI 10.17487/RFC8949, December 2020, . Authors' Addresses John Preuß Mattsson Ericsson AB Email: john.mattsson@ericsson.com Göran Selander Ericsson AB Email: goran.selander@ericsson.com Shahid Raza RISE AB Email: shahid.raza@ri.se Joel Höglund RISE AB Email: joel.hoglund@ri.se Martin Furuhed Nexus Group Email: martin.furuhed@nexusgroup.com