---
title: IANA Registry Updates for TLS and DTLS
abbrev: TLS and DTLS IANA Registry Updates
docname: draft-ietf-tls-rfc8447bis-latest
number: 9847
obsoletes:
updates: 8447
submissiontype: IETF
category: std
v: 3
ipr: trust200902
area: SEC
workgroup: TLS
keyword:
date: 2025-10
consensus: true
stand_alone: yes
smart_quotes: no
pi: [toc, sortrefs, symrefs]
author:
-
ins: J. Salowey
name: Joe Salowey
organization: Venafi CyberArk
email: joe@salowey.net
-
ins: S. Turner
name: Sean Turner
organization: sn3rd
email: sean@sn3rd.com
normative:
informative:
--- abstract
<!-- [rfced] Note that we have updated the short title, which appears in the
running header in the PDF output, as follows. Please let us know any objections.
Original:
(D)TLS IANA Registry Updates
Current:
TLS and DTLS IANA Registry Updates
-->
<!-- [rfced] Please insert any keywords (beyond those that appear in the title)
for use on https://www.rfc-editor.org/search. -->
<!-- [rfced] FYI - We will do the following when we convert the file to RFCXML:
- Update relevant URLs to be clickable in the HTML and PDF outputs
-->
<!-- [rfced] Because this document updates RFC 8447, please
review the errata reported for RFC 8447
(https://www.rfc-editor.org/errata/rfc8447)
and let us know if you confirm our opinion that none of them
are relevant to the content of this document.
-->
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.
--- middle
# Introduction
This document instructs IANA to make changes to a number of the IANA
registries related to Transport Layer Security (TLS) and Datagram
Transport Layer Security (DTLS). These changes update the changes made
in {{!RFC8447}}.
This specification 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.
This specification also updates the registration request instructions.
# Terminology
{::boilerplate bcp14-tagged}
<!-- [rfced] In the sentence below, is the intention to have consensus
to leave one item or multiple items marked?
Original:
The IETF might have consensus to leave an items marked as "N" on the
basis of its having limited applicability or usage constraints.
Perhaps (Singular):
The IETF might have consensus to leave an item marked as "N" on the
basis of the item having limited applicability or usage constraints.
Or (Plural):
The IETF might have consensus to leave items marked as "N" on the
basis of the items having limited applicability or usage constraints.
-->
# Updating "Recommended" Column's Values
The instructions in this document update the "Recommended" column,
originally added in {{RFC8447}} to add a third value, "D",
indicating that a value is discouraged. The permitted values
of the "Recommended" column are:
Y:
: Indicates that the IETF has consensus that the
item is RECOMMENDED. This only means that the associated
mechanism is fit for the purpose for which it was defined.
Careful reading of the documentation for the mechanism is
necessary to understand the applicability of that mechanism.
The IETF could recommend mechanisms that have limited
applicability but will provide applicability statements that
describe any limitations of the mechanism or necessary constraints
on its use.
N:
: Indicates that the item has not been evaluated by
the IETF and that the IETF has made no statement about the
suitability of the associated mechanism. This does not necessarily
mean that the mechanism is flawed, only that no consensus exists.
The IETF might have consensus to leave an items item marked as "N" on
the basis of its the item having limited applicability or usage constraints.
D:
: Indicates that the item is discouraged. This marking could be used to identify
mechanisms that might result in problems if they are used, such as
a weak cryptographic algorithm or a mechanism that might cause
interoperability problems in deployment. When marking a registry entry as
"D", either the "Reference" or the "Comment" column MUST include sufficient
information to determine why the marking has been applied. Implementers and
users SHOULD consult the linked references associated with the item to
determine the conditions under which the item SHOULD NOT or MUST NOT be used.
Setting a value to "Y" or "D" or transitioning the value from "Y" or "D" in the "Recommended" column requires
IETF Standards Action with Expert Review or IESG Approval {{!RFC8126}}. Not all items defined
in Standards Track RFCs need to be set
to "Y" or "D". Any item not otherwise specified is set to "N". The column is
blank for values that are unassigned or reserved unless specifically set.
## Recommended Note {#rec-note}
Existing registries have a note on the meaning of the "Recommended" column. For the
registries discussed in the subsequent sections, this note is updated
with a sentence describing the "D" value as follows:
{:quote}
> Note: If the "Recommended" column is set to "N", it does not necessarily mean
that it is flawed; rather, it indicates that the item has not
been through the IETF consensus process, has limited applicability, or
is intended only for specific use cases. If the "Recommended" column
is set to "D", the item is discouraged and SHOULD NOT or MUST NOT be used,
depending upon the situation; consult the item's references for clarity.
# TLS ExtensionType Values Registry
In order to reflect the changes in the "Recommended" column allocation,
IANA has updated the "TLS ExtensionType Values" registry as follows:
- Adjusted the registration procedure related to setting the "Recommended" column as follows:
Setting a value to "Y" or "D" or transitioning the value from
"Y" or "D" in the "Recommended" column requires
IETF Standards Action with Expert Review or IESG Approval [RFC8126].
- Added a reference to this document under the reference heading.
- Updated the "Recommended" column with the changes listed below. Entries
keep their existing "Y" and "N" entries except for the entries in the following table.
IANA has added a reference to this document for these entries.
<!-- [rfced] FYI - We have reordered the values in Table 1 to reflect
how they are listed in the "TLS ExtensionType Values" registry.
-->
|Value | Extension Name | Recommended |
|:-----|:------------------------------------|------------:|
|4 |truncated_hmac | D |
|40 |Reserved | D |
|46 |Reserved | D |
|53 |connection_id (deprecated) | D |
- Updated the note on the "Recommended" column with text in {{rec-note}}.
- For the truncated_hmac, added the following link to the "Reference" column: https://www.iacr.org/archive/asiacrypt2011/70730368/70730368.pdf
- For the two Reserved values above, added the following link in the "Reference" column: https://mailarchive.ietf.org/arch/msg/tls-reg-review/5BD62HBFjo_AsW-Y8ohVuWEe1gI/
# TLS Cipher Suites Registry
Several categories of cipher suites are discouraged for general use and
are marked as "D".
Cipher suites that use NULL encryption do not provide the confidentiality
normally expected of TLS. Protocols and applications are often designed
to require confidentiality as a security property. These
cipher suites MUST NOT be used in those cases.
Cipher suites marked as EXPORT use weak ciphers and were deprecated in
TLS 1.1 {{!RFC4346}}.
Cipher suites marked as anon do not provide any authentication, are
vulnerable to on-path attacks, and were deprecated in TLS 1.1
{{!RFC4346}}.
RC4 is a weak cipher and is deprecated in {{!RFC7465}}.
DES and the International Data Encryption Algorithm (IDEA) are not considered secure for general use and were deprecated in {{!RFC5469}}. MD5 and SHA-1 are also not secure for general use and were deprecated in {{!RFC9155}}.
In order to reflect the changes in the "Recommended" column allocation,
IANA has updated the "TLS Cipher Suites" registry as follows:
- Adjusted the registration procedure related to setting the "Recommended" column as follows:
Setting a value to "Y" or "D" or transitioning the value from
"Y" or "D" in the "Recommended" column requires
IETF Standards Action with Expert Review or IESG Approval [RFC8126].
- Added a reference to this document under the reference heading.
- Updated the "Recommended" column with the changes listed below. Entries
keep their existing "Y" and "N" entries except for the entries in following table.
IANA has added a reference to this document for these entries. This document does not
make any changes to the "DTLS-OK" column.
| Value | Description | Recommended |
|:------|:---------------------------------------------|-----------:|
| 0x00,0x1E | TLS_KRB5_WITH_DES_CBC_SHA | D |
| 0x00,0x20 | TLS_KRB5_WITH_RC4_128_SHA | D |
| 0x00,0x21 | TLS_KRB5_WITH_IDEA_CBC_SHA | D |
| 0x00,0x22 | TLS_KRB5_WITH_DES_CBC_MD5 | D |
| 0x00,0x24 | TLS_KRB5_WITH_RC4_128_MD5 | D |
| 0x00,0x25 | TLS_KRB5_WITH_IDEA_CBC_MD5 | D |
| 0x00,0x26 | TLS_KRB5_EXPORT_WITH_DES_CBC_40_SHA | D |
| 0x00,0x27 | TLS_KRB5_EXPORT_WITH_RC2_CBC_40_SHA | D |
| 0x00,0x28 | TLS_KRB5_EXPORT_WITH_RC4_40_SHA | D |
| 0x00,0x29 | TLS_KRB5_EXPORT_WITH_DES_CBC_40_MD5 | D |
| 0x00,0x2A | TLS_KRB5_EXPORT_WITH_RC2_CBC_40_MD5 | D |
| 0x00,0x2B | TLS_KRB5_EXPORT_WITH_RC4_40_MD5 | D |
| 0x00,0x2C | TLS_PSK_WITH_NULL_SHA | D |
| 0x00,0x8A | TLS_PSK_WITH_RC4_128_SHA | D |
| 0x00,0xB0 | TLS_PSK_WITH_NULL_SHA256 | D |
| 0x00,0xB1 | TLS_PSK_WITH_NULL_SHA384 | D |
| 0xC0,0x06 | TLS_ECDHE_ECDSA_WITH_NULL_SHA | D |
| 0xC0,0x07 | TLS_ECDHE_ECDSA_WITH_RC4_128_SHA | D |
| 0xC0,0x10 | TLS_ECDHE_RSA_WITH_NULL_SHA | D |
| 0xC0,0x11 | TLS_ECDHE_RSA_WITH_RC4_128_SHA | D |
| 0xC0,0x33 | TLS_ECDHE_PSK_WITH_RC4_128_SHA | D |
| 0xC0,0x39 | TLS_ECDHE_PSK_WITH_NULL_SHA | D |
| 0xC0,0x3A | TLS_ECDHE_PSK_WITH_NULL_SHA256 | D |
| 0xC0,0x3B | TLS_ECDHE_PSK_WITH_NULL_SHA384 | D |
| 0xC0,0xB4 | TLS_SHA256_SHA256 | D |
| 0xC0,0xB5 | TLS_SHA384_SHA384 | D |
- Updated the note on the "Recommended" column with text in {{rec-note}}.
# TLS Supported Groups Registry
In order to reflect the changes in the "Recommended" column allocation,
IANA has updated the "TLS Supported Groups" registry as follows:
- Updated the registration policy to include:
Setting a value to "Y" or "D" or transitioning the value from
"Y" or "D" in the "Recommended" column requires
IETF Standards Action with Expert Review or IESG Approval [RFC8126].
- Added a reference to this document under the reference heading.
- Updated the "Recommended" column with the changes listed below. Entries
keep their existing "Y" and "N" entries except for the entries in following table.
IANA has added a reference to this document for these entries.
| Value | Description | Recommended |
|:-|:-|-:|
| 1 |sect163k1 | D |
| 2 | sect163r1 | D |
| 3 | sect163r2 | D |
| 4 | sect193r1 | D |
| 5 | sect193r2 | D |
| 6 | sect233k1 | D |
| 7 | sect233r1 | D |
| 8 | sect239k1 | D |
| 15 | secp160k1 | D |
| 16 | secp160r1 | D |
| 17 | secp160r2 | D |
| 18 | secp192k1 | D |
| 19 | secp192r1 | D |
| 20 | secp224k1 | D |
| 21 | secp224r1 | D |
- Updated the note on the "Recommended" column with text in {{rec-note}}.
- Removed the "Elliptic curve groups" note from the registration
procedures table.
- For each of the entries above, added the following link to the
"Comment" column: https://datatracker.ietf.org/meeting/118/materials/slides-118-tls-rfc8447bis-00
# TLS Exporter Labels Registry
This document updates the registration procedure for the "TLS Exporter
Labels" registry and updates the "Recommended" column allocation.
IANA has updated the "TLS Exporter Labels" registry as follows:
- Changed the registration procedure from Specification Required to
Expert Review and updated it to include:
Setting a value to "Y" or "D" or transitioning the value from
"Y" or "D" in the "Recommended" column requires
IETF Standards Action with Expert Review or IESG Approval [RFC8126].
- Added a reference to this document under the reference heading.
- Entries kept their existing "Recommended" column "Y" and "N" entries.
- Updated the note on the "Recommended" column with text in {{rec-note}}.
- Updated the note on the role of the expert reviewer as follows.
{:quote}
> Note: The role of the designated expert is described in {{RFC8447, Section 17}}.
Even though this registry does not require a specification, the
designated expert {{!RFC8126}} will strongly encourage registrants
to provide a link to a publicly available specification. An
Internet-Draft (that is posted and never published as an RFC)
or a document from another standards body, industry consortium,
university site, etc. is suitable for these purposes.
The expert may provide more in-depth reviews, but their approval
should not be taken as an endorsement of the exporter label. The
expert also verifies that the label is a string consisting of
printable ASCII characters beginning with "EXPORTER". IANA MUST
also verify that one label is not a prefix of any other label.
For example, labels "key" or "master secretary" are forbidden.
- Renamed the "Note" column to "Comment".
# TLS Certificate Types Registry
In order to reflect the changes in the "Recommended" column allocation,
IANA has updated the "TLS Certificate Types" registry as follows:
- Adjusted the registration procedure related to setting the "Recommended" column as follows:
Setting a value to "Y" or "D" or transitioning the value from
"Y" or "D" in the "Recommended" column requires
IETF Standards Action with Expert Review or IESG Approval [RFC8126].
- Added a reference to this document under the reference heading.
- Entries kept their existing "Recommended" column "Y" and "N" entries.
- Updated the note on the "Recommended" column with text in {{rec-note}}.
# TLS HashAlgorithm Registry
TLS 1.0 and TLS 1.1 were deprecated {{!RFC8996}}, {{!RFC8996}}; TLS 1.2 will
be in use for some time. In order to reflect the changes in the "Recommended"
column allocation, IANA has updated the "TLS HashAlgorithm" registry
as follows:
- Updated the registration procedure to include:
Setting a value to "Y" or "D" or transitioning the value from
"Y" or "D" in the "Recommended" column requires
IETF Standards Action with Expert Review or IESG Approval [RFC8126].
- Added a reference to this document under the reference heading.
- Updated the "TLS HashAlgorithm" registry to add a "Recommended" column
as follows:
| Value | Description | Recommended |
|:---- |:-------------|------------:|
| 0 | none | Y |
| 1 | md5 | D |
| 2 | sha1 | D |
| 3 | sha224 | D |
| 4 | sha256 | Y |
| 5 | sha384 | Y |
| 6 | sha512 | Y |
| 8 | Intrinsic | Y |
- Added a note on the "Recommended" column with text in {{rec-note}}.
# TLS SignatureAlgorithm Registry
TLS 1.0 and TLS 1.1 were deprecated {{!RFC8996}}, TLS 1.2 will
be in use for some time. In order to reflect the changes in the "Recommended"
column allocation, IANA has updated the "TLS SignatureAlgorithm" registry
as follows:
- Updated the registration procedure to include:
Setting a value to "Y" or "D" or transitioning the value from
"Y" or "D" in the "Recommended" column requires
IETF Standards Action with Expert Review or IESG Approval [RFC8126].
- Added a reference to this document under the reference heading.
- Updated the "TLS SignatureAlgorithm" registry to add a "Recommended"
column as follows:
|Value | Description | Recommended |
|:-----|:-------------|------------:|
| 0 | anonymous| N |
| 1 | rsa | Y |
| 2 | dsa | N |
| 3 | ecdsa | Y |
| 7 | ed25519 | Y |
| 8 | ed448 | Y |
| 64 | gostr34102012_256 | N |
| 65 | gostr34102012_512 | N |
- Added a note on the "Recommended" column with text in {{rec-note}}.
# TLS ClientCertificateType Identifiers Registry
TLS 1.0 and TLS 1.1 were deprecated {{!RFC8996}}, TLS 1.2 will
be in use for some time. In order to reflect the changes in the "Recommended"
column allocation, IANA has updated the "TLS ClientCertificateType Identifiers"
registry as follows:
- Updated the registration procedure to include:
Setting a value to "Y" or "D" or transitioning the value from
"Y" or "D" in the "Recommended" column requires
IETF Standards Action with Expert Review or IESG Approval [RFC8126].
- Added a reference to this document under the reference heading.
- Updated the "TLS ClientCertificateType Identifiers" registry to add a "Recommended"
column as follows:
| Value | Description | Recommended |
|:------|:-------------|------------:|
| 1 | rsa_sign | Y |
| 2 | dss_sign | N |
| 3 | rsa_fixed_dh | N |
| 4 | dss_fixed_dh | N |
| 5 | rsa_ephemeral_dh_RESERVED | D |
| 6 | dss_ephemeral_dh_RESERVED | D |
| 20 | fortezza_dms_RESERVED | D |
| 64 | ecdsa_sign | Y |
| 65 | rsa_fixed_ecdh | N |
| 66 | ecdsa_fixed_ecdh | N |
| 67 | gost_sign256 | N |
| 68 | gost_sign512 | N |
- Added a note on the "Recommended" column with text in {{rec-note}}.
# TLS PskKeyExchangeMode Registry
In order to reflect the changes in the "Recommended" column allocation,
IANA has updated the "TLS PskKeyExchangeMode" registry as follows:
- Updated the registration procedure to include:
Setting a value to "Y" or "D" or transitioning the value from
"Y" or "D" in the "Recommended" column requires
IETF Standards Action with Expert Review or IESG Approval [RFC8126].
- Added a reference to this document under the reference heading.
- Entries kept their existing "Recommended" column "Y" and "N" entries.
- Updated note on the "Recommended" column with text in {{rec-note}}.
# TLS SignatureScheme Registry
In order to reflect the changes in the "Recommended" column allocation,
IANA has updated the "TLS SignatureScheme" registry as follows:
- Updated the registration procedure to include:
Setting a value to "Y" or "D" or transitioning the value from
"Y" or "D" in the "Recommended" column requires
IETF Standards Action with Expert Review or IESG Approval [RFC8126].
- Added a reference to this document under the reference heading.
- Entries kept their existing "Recommended" column "Y" and "N" entries.
- Updated note on the "Recommended" column with text in {{rec-note}}.
# Adding "Comment" Column
IANA has added a "Comment" column to the following registries:
- TLS ExtensionType Values
- TLS Application-Layer Protocol Negotiation (ALPN) Protocol IDs
- TLS CachedInformationType Values
- TLS Certificate Compression Algorithm IDs
- TLS ClientCertificateType Identifiers
- TLS Cipher Suites
- TLS ContentType
- TLS EC Point Formats
- TLS EC Curve Types
- TLS Supplemental Data Formats (SupplementalDataType)
- TLS UserMappingType Values
- TLS SignatureAlgorithm
- TLS HashAlgorithm
- TLS Authorization Data Formats
- TLS Heartbeat Message Types
- TLS Heartbeat Modes
- TLS SignatureScheme
- TLS PskKeyExchangeMode
- TLS KDF Identifiers
- TLS SSLKEYLOGFILE Labels
This list of registries is all registries that do not already have a
"Comment" or "Note" column or that were not orphaned by TLS 1.3.
<!--[rfced] May we remove this sentence from the end of Section 14?
This action is already listed in Section 7.
Original:
IANA is requested to rename the "Note" column to "Comment" column in
TLS Exporter Labels registry.
-->
IANA has renamed the "Note" column to "Comment" in the
"TLS Exporter Labels" registry.
# Expert Review of Current and Potential IETF and IRTF Documents
The intent of the Specification Required choice for TLS codepoints
is to allow for easy registration for codepoints associated with
protocols and algorithms that are not being actively developed inside
the IETF or IRTF. When TLS-based technologies are being developed inside
the IETF or IRTF, they should be done in coordination with the TLS WG in
order to provide appropriate review. For this reason, unless the TLS WG
Chairs indicate otherwise via email, designated
experts should decline codepoint registrations for documents that
have already been adopted or are being proposed for adoption by IETF
working groups or IRTF research groups.
# Registration Requests
Registration requests MUST be submitted in one of two ways:
1. By sending email to iana@iana.org; this email SHOULD
use an appropriate subject (e.g., "Request to register value in TLS
bar registry").
2. Using the online form at https://www.iana.org/form/protocol-assignment.
Specification Required {{RFC8126}} registry requests are registered after
a three-week review period on the advice of one or more designated
experts. However, to allow for the allocation of values prior to
publication, the designated experts may approve registration once they
are satisfied that such a specification will be published.
# Security Considerations
Recommended algorithms are regarded as secure for general use at the
time of registration; however, cryptographic algorithms and parameters
will be broken or weakened over time. It is possible that the
"Recommended" status in the registry lags behind the most recent advances
in cryptanalysis. Implementers and users need to check that the
cryptographic algorithms listed continue to provide the expected level
of security.
Designated experts ensure the specification is publicly available. They may
provide more in-depth reviews. Their review should not be taken as an
endorsement of the cipher suite, extension, supported group, etc.
# IANA Considerations
This document is entirely about changes to TLS-related IANA registries.
IANA has modified the note applied to all TLS Specification
Required registries instructing where to send registration requests as
follows:
<!--[rfced] IANA provided the following note when they notified us that their
actions were complete:
NOTE: Some text at the end of the IANA Considerations section concerning request
submission needs to be removed or replaced. Details at the end of the list of
actions.
Per this note and to reflect what appears in the TLS-related IANA registries,
we have updated the text as shown below. Please let us know if any changes are
needed.
Original:
Requests for assignments from the registry's Specification Required
range should be sent to the mailing list described in [This RFC,
Section 16]. If approved, designated experts should notify IANA
within three weeks. For assistance, please contact iana@iana.org.
Current:
| Note: Requests for registration in the "Specification Required"
| [RFC8126] range should be sent to iana@iana.org or submitted via
| IANA's application form, per [RFC 9847]. IANA will forward the
| request to the expert mailing list described in [RFC8447],
| Section 17 and track its progress. See the registration procedure
| table below for more information.
-->
{:quote}
> Note: Requests for registration in the "Specification Required" {{RFC8126}}
range should be sent to iana@iana.org or submitted via IANA's
application form, per [RFC 9847]. [RFC9847]. IANA will
forward the request to the expert mailing list described in
{{RFC8447, Section 17}} and track its progress. See the registration
procedure table below for more information.
<!-- [rfced] FYI - We have added an expansion for the following abbreviation
per Section 3.6 of RFC 7322 ("RFC Style Guide"). Please review each expansion
in the document carefully to ensure correctness.
International Data Encryption Algorithm (IDEA)
-->
<!-- [rfced] FYI - We have updated the following terms to the form on the
right to match other documents in Cluster 430. Please let us know any objections.
ciphersuite(s) > cipher suite(s)
code points > codepoints
-->
<!-- [rfced] Please review the "Inclusive Language" portion of the online
Style Guide <https://www.rfc-editor.org/styleguide/part2/#inclusive_language>
and let us know if any changes are needed. Updates of this nature typically
result in more precise language, which is helpful for readers.
Note that our script did not flag any words in particular, but this should
still be reviewed as a best practice.
-->
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