TLS 1.2 is in Feature Freeze
draft-ietf-tls-tls12-frozen-07

Transport Layer Security                                         R. Salz
Internet-Draft                                       Akamai Technologies
Intended status: Standards Track                               N. Aviram
Expires: 27 September 2025                                 26 March 2025

                      TLS 1.2 is in Feature Freeze
                     draft-ietf-tls-tls12-frozen-07

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, 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 27 September 2025               [Page 1]
Internet-Draft                tls1.2-frozen                   March 2025

   This Internet-Draft will expire on 27 September 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].  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, 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 27 September 2025               [Page 2]
Internet-Draft                tls1.2-frozen                   March 2025

2.  Implications for post-quantum cryptography

   Cryptographically relevant quantum computers, once available, are
   likely to greatly lessen the time and effort needed to break RSA,
   FFDH, or 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].  Many other countries and organizations are publishing
   their roadmaps, including the multi-national standards organization
   ETSI, [ETSI].

   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 efforts within the
   TLS Working Group 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 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.

   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 TLS

Salz & Aviram           Expires 27 September 2025               [Page 3]
Internet-Draft                tls1.2-frozen                   March 2025

      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 like "For TLS 1.3
      or later" in that entry, such as the "Comment" column.

   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

Salz & Aviram           Expires 27 September 2025               [Page 4]
Internet-Draft                tls1.2-frozen                   March 2025

   *  TLS Supplemental Data Formats (SupplementalDataType)

   *  TLS Supported Groups

   *  TLS UserMappingType Values

   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-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>.

Salz & Aviram           Expires 27 September 2025               [Page 5]
Internet-Draft                tls1.2-frozen                   March 2025

   [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

Salz & Aviram           Expires 27 September 2025               [Page 6]