TLS 1.2 is in Feature Freeze Akamai Technologies
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SEC tls TLS features Use of TLS 1.3, which fixes some known deficiencies in TLS 1.2, is growing. This document specifies that no changes will be approved for TLS 1.2 outside of urgent security fixes (as determined by TLS Working Group consensus), new TLS Exporter Labels, and new Application-Layer Protocol Negotiation (ALPN) Protocol IDs. This applies to TLS only; it does not apply to DTLS (in any DTLS version).
Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at .
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Table of Contents
  • .  Introduction
  • .  Implications for Post-Quantum Cryptography (PQC)
  • .  Security Considerations
  • .  IANA Considerations
  • .  References
    • .  Normative References
    • .  Informative References
  • Acknowledgments
  • Authors' Addresses
Introduction TLS 1.3 fixes most known deficiencies with TLS 1.2 and its use is growing. Some examples of the fixes include encrypting more of the traffic so that it is not readable by outsiders and removing most cryptographic primitives that are 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 no changes will be approved for TLS 1.2 outside of urgent security fixes (as determined by TLS Working Group consensus) and the exceptions listed in . This applies to TLS only. As such, it does not apply to DTLS, in any DTLS version.
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 . Initial discussions in the IETF community happened around the same time . In 2024, NIST released standards for , , and . Many other countries and organizations are publishing their roadmaps, including the multi-national standards organization 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 the use of Post-Quantum Cryptography (PQC) in IETF protocols . Several other working groups, including TLS , 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 effort within the TLS Working Group is focused exclusively on TLS 1.3 or later. Put bluntly, PQC for TLS 1.2 will not be specified (see ) at any time; anyone wishing to deploy PQC should expect to use TLS 1.3.
Security Considerations This entire document is about security and provides post-quantum security concerns as an additional reason to upgrade to TLS 1.3.
IANA Considerations No TLS registries are being closed by this document. Rather, this document modifies the instructions to IANA and the TLS Designated Experts to constrain the type of entries that can be added to existing registries. This document does not introduce any new limitations on the registrations for either of the following two registries:
  • TLS Application-Layer Protocol Negotiation (ALPN) Protocol IDs
  • TLS Exporter Labels
The following note has been added to the other TLS registries:
Any TLS entry added after the IESG approves publication of RFC 9851 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 note has been added to the following TLS registries:
  • 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
Any TLS registry created after this document is approved for publication should indicate whether the actions defined here are applicable.
References Normative References The Transport Layer Security (TLS) Protocol Version 1.2 This document specifies Version 1.2 of the Transport Layer Security (TLS) protocol. The TLS protocol provides communications security over the Internet. The protocol allows client/server applications to communicate in a way that is designed to prevent eavesdropping, tampering, or message forgery. [STANDARDS-TRACK] The Transport Layer Security (TLS) Protocol Version 1.3 This document specifies version 1.3 of the Transport Layer Security (TLS) protocol. TLS allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery. This document obsoletes RFC 8446, which specified TLS 1.3. This document obsoletes RFC 5246 (specifying TLS 1.2) and RFCs 5077, 6961, 7627, and 8422, all of which pertain to TLS 1.2 or earlier, and updates RFCs 5705 and 6066. This document also specifies new requirements for TLS 1.2 implementations. IANA Registry Updates for TLS and DTLS This document updates the changes to the TLS and DTLS IANA registries made in RFC 8447. It adds a new value, "D" for discouraged, to the "Recommended" column of the selected TLS registries and adds a "Comment" column to all active registries that do not already have a "Comment" column. Finally, it updates the registration request instructions. This document updates RFC 8447. Informative References Post Quantum Secure Cryptography Discussion IETF 95 Proceedings CYBER; Migration strategies and recommendations to Quantum Safe schemes European Telecommunications Standards Institute Version 1.1.1 Module-Lattice-Based Digital Signature Standard National Institute of Standards and Technology Module-Lattice-Based Key-Encapsulation Mechanism Standard National Institute of Standards and Technology Post-Quantum Cryptography (PQC) NIST Post-Quantum Use in Protocols IETF Stateless Hash-Based Digital Signature Standard National Institute of Standards and Technology Transport Layer Security IETF
Acknowledgments We gratefully acknowledge , , and of IANA for their help in revising and clarifying .
Authors' Addresses Akamai Technologies
rsalz@akamai.com
nimrod.aviram@gmail.com