Transport Layer Security R. Salz Internet-Draft Akamai Technologies Intended status: Standards Track N. Aviram Expires: 2 August 2025 29 January 2025 TLS 1.2 is in Feature Freeze draft-ietf-tls-tls12-frozen-06 Abstract Use of TLS 1.3 is growing and fixes some known deficiencies in TLS 1.2. This document specifies that outside of urgent security fixes, new TLS Exporter Labels, or new Application-Layer Protocol Negotiation (ALPN) Protocol IDs, no changes will be approved for TLS 1.2. This prescription does not pertain to DTLS (in any DTLS version); it pertains to TLS only. 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-ietf-tls-tls12-frozen/. Discussion of this document takes place on the Transport Layer Security Working Group mailing list (mailto:tls@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/tls/. Subscribe at https://www.ietf.org/mailman/listinfo/tls/. Source for this draft and an issue tracker can be found at https://github.com/tlswg/tls12-frozen. 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." Salz & Aviram Expires 2 August 2025 [Page 1] Internet-Draft tls1.2-frozen January 2025 This Internet-Draft will expire on 2 August 2025. Copyright Notice Copyright (c) 2025 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. Implications for post-quantum cryptography . . . . . . . . . 3 3. Security Considerations . . . . . . . . . . . . . . . . . . . 3 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 5. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 5.1. Normative References . . . . . . . . . . . . . . . . . . 5 5.2. Informative References . . . . . . . . . . . . . . . . . 5 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction Use of TLS 1.3 [TLS13] is growing, and it fixes most known deficiencies with TLS 1.2 [TLS12], such as encrypting more of the traffic so that it is not readable by outsiders and removing most cryptographic primitives now considered weak. Importantly, TLS 1.3 enjoys robust security proofs. Both versions have several extension points, so items like new cryptographic algorithms, new supported groups (formerly "named curves"), etc., can be added without defining a new protocol. This document specifies that outside of urgent security fixes, and the exceptions listed in Section 4, no changes will be approved for TLS 1.2. This prescription does not pertain to DTLS (in any DTLS version); it pertains to TLS only. Salz & Aviram Expires 2 August 2025 [Page 2] Internet-Draft tls1.2-frozen January 2025 2. Implications for post-quantum cryptography Cryptographically relevant quantum computers, once available, will have a huge impact on RSA, FFDH, and ECC which are currently used in TLS. In 2016, the US National Institute of Standards and Technology started a multi-year effort to standardize algorithms that will be "safe" once quantum computers are feasible [PQC]. First discussions in the IETF community happened around the same time [CFRGSLIDES]. In 2024 NIST released standards for [ML-KEM], [ML-DSA], and [SLH-DSA]. While industry was waiting for NIST to finish standardization, the IETF has had several efforts underway. A working group was formed in early 2023 to work on use of PQC in IETF protocols, [PQUIPWG]. Several other working groups, including TLS [TLSWG], are working on drafts to support hybrid algorithms and identifiers, for use during a transition from classic to a post- quantum world. For TLS it is important to note that the focus of these efforts is exclusively TLS 1.3 or later. Put bluntly, post-quantum cryptography for TLS 1.2 WILL NOT be supported (see Section 4) at any time and anyone wishing to deploy post-quantum cryptography should expect to be using TLS 1.3. 3. Security Considerations This entire document is about security, and provides post-quantum concerns as an additional reason to upgrade to TLS 1.3. 4. IANA Considerations No registries [TLS13REG] are being closed by this document. Rather, this document modifies the instructions to IANA and the TLS Designed Experts to constrain what type of entries can be added. There are no limits on the registrations for either of the following two registries: * TLS Application-Layer Protocol Negotiation (ALPN) Protocol IDs * TLS Exporter Labels All other registries should have this Note added to them: Any entry added after the IESG approves publication of {THIS RFC} is intended for TLS 1.3 or later, and makes no requirement on DTLS. Such entries should have an informal indication indication like "For TLS 1.3 or later" in that entry, such as the "Comment" column. Salz & Aviram Expires 2 August 2025 [Page 3] Internet-Draft tls1.2-frozen January 2025 At the time of publication, the list of other registries is as follows: * TLS Alerts * TLS Authorization Data Formats * TLS CachedInformationType Values * TLS Certificate Compression Algorithm IDs * TLS Certificate Status Types * TLS Certificate Types * TLS Cipher Suites * TLS ClientCertificateType Identifiers * TLS ContentType * TLS EC Curve Types * TLS EC Point Formats * TLS ExtensionType Values * TLS HandshakeType * TLS HashAlgorithm * TLS Heartbeat Message Types * TLS Heartbeat Modes * TLS KDF Identifiers * TLS PskKeyExchangeMode * TLS SignatureAlgorithm * TLS SignatureScheme * TLS Supplemental Data Formats (SupplementalDataType) * TLS Supported Groups * TLS UserMappingType Values Salz & Aviram Expires 2 August 2025 [Page 4] Internet-Draft tls1.2-frozen January 2025 Any registries created after this document is approved for publication should indicate whether the actions defined here are applicable. 5. References 5.1. Normative References [TLS12] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/RFC5246, August 2008, . [TLS13] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", Work in Progress, Internet-Draft, draft- ietf-tls-rfc8446bis-11, 14 September 2024, . [TLS13REG] Salowey, J. A. and S. Turner, "IANA Registry Updates for TLS and DTLS", Work in Progress, Internet-Draft, draft- ietf-tls-rfc8447bis-10, 3 November 2024, . 5.2. Informative References [CFRGSLIDES] McGrew, D., "Post Quantum Secure Cryptography Discussion", n.d., . [ML-DSA] "Module-Lattice-Based Key Digital Signature Standard", August 2024, . [ML-KEM] "Module-Lattice-Based Key-Encapsulation Mechanism Standard", August 2024, . [PQC] "Post-Quantum Cryptography", January 2017, . [PQUIPWG] "Post-Quantum Use in Protocols", n.d., . [SLH-DSA] "Stateless Hash-Based Key-Digital Signature Standard", August 2024, . Salz & Aviram Expires 2 August 2025 [Page 5] Internet-Draft tls1.2-frozen January 2025 [TLSWG] "Transport Layer Security", n.d., . Acknowledgments We gratefully acknowledge Amanda Baber, David Dong, and Sabrina Tanamal of IANA for their help in revising and clarifying Section 4. Authors' Addresses Rich Salz Akamai Technologies Email: rsalz@akamai.com Nimrod Aviram Email: nimrod.aviram@gmail.com Salz & Aviram Expires 2 August 2025 [Page 6]