LAMPS WG R. Mahy Internet-Draft Wire Intended status: Informational 23 October 2023 Expires: 25 April 2024 X.509 Certificate Extended Key Usage (EKU) for Instant Messaging URIs draft-mahy-lamps-im-keyusage-00 Abstract RFC 5280 specifies several extended key purpose identifiers (KeyPurposeIds) for X.509 certificates. This document defines Instant Messaging (IM) identity KeyPurposeIds for inclusion in the Extended Key Usage (EKU) extension of X.509 v3 public key certificates About This Document This note is to be removed before publishing as an RFC. The latest revision of this draft can be found at https://example.com/LATEST. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-mahy-lamps-im- keyusage/. Discussion of this document takes place on the LAMPS WG Working Group mailing list (mailto:lamps@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/lamps/. Subscribe at https://www.ietf.org/mailman/listinfo/lamps/. Source for this draft and an issue tracker can be found at https://github.com/rohan-wire/mahy-lamps-im-keyusage. 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/. 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." Mahy Expires 25 April 2024 [Page 1] Internet-Draft extendedKeyUsage for IM URIs October 2023 This Internet-Draft will expire on 25 April 2024. Copyright Notice Copyright (c) 2023 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 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 2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3 3. The IM URI Extended Key Usage . . . . . . . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . 3 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 3 6.1. Normative References . . . . . . . . . . . . . . . . . . 3 6.2. Informative References . . . . . . . . . . . . . . . . . 4 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction Instant Messaging (IM) systems using the Messaging Layer Security (MLS) [RFC9420] protocol can incorporate per-client identity certificate credentials. The subjectAltName of these certificates can be an IM URI, for example. Since IM clients could be very numerous, operators are reticent to issue certificates for these users that might accidentally be used to validate a TLS connection because it has the KeyPurposeId id-kp-serverAuth or id-kp-clientAuth. An explanation of MLS credentials as they apply to Instant Messaging is described in [I-D.barnes-mimi-identity-arch]. These credentials are expected to be heavily used in the More Instant Messaging Interoperability (MIMI) Working Group. Mahy Expires 25 April 2024 [Page 2] Internet-Draft extendedKeyUsage for IM URIs October 2023 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. The IM URI Extended Key Usage This specification defines the KeyPurposeId id-kp-imUri, which is used for signing messages to prove the identity of an Instant Messaging client. id-kp OBJECT IDENTIFIER ::= { iso(1) identified-organization(3) dod(6) internet(1) security(5) mechanisms(5) pkix(7) kp(3) } id-kp-imUri OBJECT IDENTIFIER ::= { id-kp TBD } 4. Security Considerations The Security Considerations of [RFC5280] are applicable to this document. This extended key purpose does not introduce new security risks but instead reduces existing security risks by providing means to identify if the certificate is generated to sign IM credentials. 5. IANA Considerations IANA is requested to register the following OIDs in the "SMI Security for PKIX Extended Key Purpose" registry (1.3.6.1.5.5.7.3). These OIDs are defined in Section 4. +=========+=============+============+ | Decimal | Description | References | +=========+=============+============+ | TBD | id-kp-imUri | This-RFC | +---------+-------------+------------+ Table 1 6. References 6.1. Normative References Mahy Expires 25 April 2024 [Page 3] Internet-Draft extendedKeyUsage for IM URIs October 2023 [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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . 6.2. Informative References [I-D.barnes-mimi-identity-arch] Barnes, R. and R. Mahy, "Identity for E2E-Secure Communications", Work in Progress, Internet-Draft, draft- barnes-mimi-identity-arch-00, 24 October 2022, . [RFC9420] Barnes, R., Beurdouche, B., Robert, R., Millican, J., Omara, E., and K. Cohn-Gordon, "The Messaging Layer Security (MLS) Protocol", RFC 9420, DOI 10.17487/RFC9420, July 2023, . Author's Address Rohan Mahy Wire Email: rohan.mahy@wire.com Mahy Expires 25 April 2024 [Page 4]