TLS 1.2 is in Feature Freeze
draft-ietf-tls-tls12-frozen-06

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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Copyright Notice

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   document authors.  All rights reserved.

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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.

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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.

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   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

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   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,
              <https://www.rfc-editor.org/rfc/rfc5246>.

   [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,
              <https://datatracker.ietf.org/doc/html/draft-ietf-tls-
              rfc8446bis-11>.

   [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,
              <https://datatracker.ietf.org/doc/html/draft-ietf-tls-
              rfc8447bis-10>.

5.2.  Informative References

   [CFRGSLIDES]
              McGrew, D., "Post Quantum Secure Cryptography Discussion",
              n.d., <https://www.ietf.org/proceedings/95/slides/slides-
              95-cfrg-4.pdf>.

   [ML-DSA]   "Module-Lattice-Based Key Digital Signature Standard",
              August 2024, <https://csrc.nist.gov/pubs/fips/204/final>.

   [ML-KEM]   "Module-Lattice-Based Key-Encapsulation Mechanism
              Standard", August 2024,
              <https://csrc.nist.gov/pubs/fips/203/final>.

   [PQC]      "Post-Quantum Cryptography", January 2017,
              <https://csrc.nist.gov/projects/post-quantum-
              cryptography>.

   [PQUIPWG]  "Post-Quantum Use in Protocols", n.d.,
              <https://datatracker.ietf.org/wg/pquip/about/>.

   [SLH-DSA]  "Stateless Hash-Based Key-Digital Signature Standard",
              August 2024, <https://csrc.nist.gov/pubs/fips/205/final>.

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   [TLSWG]    "Transport Layer Security", n.d.,
              <https://datatracker.ietf.org/wg/tls/about/>.

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

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