TLS 1.2 is in Feature Freeze
draft-ietf-tls-tls12-frozen-08

Transport Layer Security                                         R. Salz
Internet-Draft                                       Akamai Technologies
Intended status: Standards Track                               N. Aviram
Expires: 5 October 2025                                     3 April 2025

                      TLS 1.2 is in Feature Freeze
                     draft-ietf-tls-tls12-frozen-08

Abstract

   Use of TLS 1.3, which fixes some known deficiencies in TLS 1.2, is
   growing.  This document specifies that outside of urgent security
   fixes (as determine by TLS WG consensus), 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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   This Internet-Draft will expire on 5 October 2025.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Implications for Post-Quantum Cryptography (PQC)  . . . . . .   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].  Examples of this include
   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.  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 (as
   determine by TLS WG consensus), and the exceptions listed in
   Section 4, no changes will be approved for TLS 1.2.

   This prescription pertains to TLS only.  As such, it does not pertain
   to DTLS, in any DTLS version.

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2.  Implications for Post-Quantum Cryptography (PQC)

   Cryptographically relevant quantum computers, once available, are
   likely to greatly lessen the time and effort needed to break RSA,
   finite-field-based Diffie-Hellman (FFDH), or Elliptic Curve
   Cryptography (ECC) which are currently used in TLS.  In 2016, the US
   National Institute of Standards and Technology (NIST) 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].  Many other countries and organizations are publishing
   their roadmaps, including the multi-national standards organization
   ETSI, [ETSI].

   While the 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 Post-Quantum Cryptography
   (PQC) in IETF protocols [PQUIPWG].  Several other working groups,
   including TLS [TLSWG], are working on specifications to support
   hybrid algorithms and identifiers, for use during a transition from
   classic to a post-quantum world.

   It is important to note that the focus of efforts within the TLS
   Working Group is exclusively TLS 1.3 or later.  Put bluntly, PQC for
   TLS 1.2 will not be specified (see Section 4) at any time and anyone
   wishing to deploy PQC 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 TLS 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 to
   existing registries.

   This document does not introduce any new limits on the registrations
   for either of the following two registries:

   *  TLS Application-Layer Protocol Negotiation (ALPN) Protocol IDs

   *  TLS Exporter Labels

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   All other TLS registries should have this Note added to them:  Any
      TLS entry added after the IESG approves publication of {THIS RFC}
      is intended for TLS 1.3 or later, and makes no similar requirement
      on DTLS.  Such entries should have an informal indication like
      "For TLS 1.3 or later" in that entry, such as the "Comment"
      column.

   At the time of publication, the list of other TLS 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

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   *  TLS SignatureScheme

   *  TLS Supplemental Data Formats (SupplementalDataType)

   *  TLS Supported Groups

   *  TLS UserMappingType Values

   Any TLS registry 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-12, 17 February 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-tls-
              rfc8446bis-12>.

   [TLS13REG] Salowey, J. A. and S. Turner, "IANA Registry Updates for
              TLS and DTLS", Work in Progress, Internet-Draft, draft-
              ietf-tls-rfc8447bis-11, 11 March 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-tls-
              rfc8447bis-11>.

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>.

   [ETSI]     "CYBER; Migration strategies and recommendations to
              Quantum Safe schemes", n.d.,
              <https://www.etsi.org/deliver/
              etsi_tr/103600_103699/103619/01.01.01_60/
              tr_103619v010101p.pdf>.

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

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   [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>.

   [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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