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.
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This Internet-Draft will expire on 27 September 2025.
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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]. 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.
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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
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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
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* 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>.
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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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