TLS S. Farrell Internet-Draft Trinity College Dublin Intended status: Best Current Practice 15 December 2024 Expires: 18 June 2025 Post-Quantum Guidance for TLS. draft-farrell-tls-pqg-00 Abstract We provide guidance on the use of post-quantum algorithms for those deploying applications using TLS. 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." This Internet-Draft will expire on 18 June 2025. Copyright Notice Copyright (c) 2024 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. Farrell Expires 18 June 2025 [Page 1] Internet-Draft PQ Guidance for TLS December 2024 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Start using hybrid KEMs . . . . . . . . . . . . . . . . . . . 2 4. Do nothing for now on signatures . . . . . . . . . . . . . . 3 5. Security Considerations . . . . . . . . . . . . . . . . . . . 3 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 8. Normative References . . . . . . . . . . . . . . . . . . . . 3 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction [[This is not an "official" TLS WG work item, but is being proposed as such. The source for this is in https://github.com/sftcd/pqg/ PRs are welcome there too.]] Due to concerns about the possible future existence of a cryptographically relevant quantum computer (CRQC), additional TLS [RFC8446] codepoints have been defined for algorithms that are hoped to remain secure even in the face of a CRQC. Adding code-points for to the relevant IANA registries with the RECOMMENDED column set to 'n' doesn't require IETF consensus. This means that anyone can register code-points for their favoured approach. In particular various government entities in various countries have made contradictory recommendations in this space, leading to potential confusion for those deploying applilcations using TLS. This document sets out a deliberately consise sets of recommendations for typical uses of post-quantum algorithms. This assumes the reader is familiar with the topic. 2. Terminology 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. Start using hybrid KEMs The main recommendation is to move as soon as practical to use of hybrid KEMs, such as X25519MLKEM768. Once it becomes practical to do the above, we do not recommend use of non-hybrid groups. Farrell Expires 18 June 2025 [Page 2] Internet-Draft PQ Guidance for TLS December 2024 4. Do nothing for now on signatures We recommend taking no action at all at this point in time in relation to signatures. 5. Security Considerations TBD 6. Acknowledgements TBD 7. IANA Considerations TBD, but probably not needed. 8. 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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, . Author's Address Stephen Farrell Trinity College Dublin Dublin 2 Ireland Phone: +353-1-896-2354 Email: stephen.farrell@cs.tcd.ie Farrell Expires 18 June 2025 [Page 3]