Transport Layer Security (TLS) Extensions

Created

2005-11-15

Last Updated

2026-08-11

Related Registry Group(s)

[Transport Layer Security (TLS) Parameters]

Available Formats

XML
HTML
TXT

Registries Included Below

• TLS ExtensionType Values
• TLS Certificate Types
• TLS Certificate Status Types
• TLS Application-Layer Protocol Negotiation (ALPN) Protocol IDs
• TLS CachedInformationType Values
• TLS Certificate Compression Algorithm IDs

TLS ExtensionType Values

Expert(s)

Yoav Nir, Rich Salz, Nick Sullivan

Reference

[RFC 9846][RFC 8447][RFC 9146][RFC 9851][RFC 9847]

Note

If the "Specification Required" [RFC 8126] procedure applies, 
registration requests can be sent to iana@iana.org or submitted via 
IANA's [application form], per [RFC 9847]. IANA 
will forward the submission to the expert mailing list described in 
[RFC 8447, Section 17] and track its progress. See the registration 
procedure table below for more information.
    

Note

The role of the designated expert is described in [RFC 8447].
The designated expert [RFC 8126] ensures that the specification is
publicly available.  It is sufficient to have an Internet-Draft
(that is posted and never published as an RFC) or a document from
another standards body, industry consortium, university site, etc.
The expert may provide more in-depth reviews, but their approval
should not be taken as an endorsement of the extension.  
    

Note

As specified in [RFC 8126], assignments made in the Private Use
space are not generally useful for broad interoperability.  It is
the responsibility of those making use of the Private Use range to
ensure that no conflicts occur (within the intended scope of use).
For widespread experiments, temporary reservations are available.
    

Note

If the "Recommended" column is set to "N", it does not necessarily 
mean that it is flawed; rather, it indicates that the item either 
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.
    

Note

Abbreviations that may appear in the "TLS 1.3" field include "CH" 
(ClientHello), "SH" (ServerHello), "EE" (EncryptedExtensions), "CT" 
(Certificate), "CR" (CertificateRequest), "NST" (NewSessionTicket), 
and "HRR" (HelloRetryRequest).
    

Note

The addition of the "CR" to the "TLS 1.3" column for the
server_name(0) extension only marks the extension as valid in a 
ClientCertificateRequest created as part of client-generated
authenticator requests.
    

Note

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.
    

Available Formats

CSV

TLS Certificate Types

Expert(s)

Yoav Nir, Rich Salz, Nick Sullivan

Reference

[RFC 6091][RFC 9846][RFC 8447][RFC 9851][RFC 9847]

Note

If the "Specification Required" [RFC 8126] procedure applies, 
registration requests can be sent to iana@iana.org or submitted via 
IANA's [application form], per [RFC 9847]. IANA 
will forward the submission to the expert mailing list described in 
[RFC 8447, Section 17] and track its progress. See the registration 
procedure table below for more information.
    

Note

The role of the designated expert is described in [RFC 8447].
The designated expert [RFC 8126] ensures that the specification is
publicly available.  It is sufficient to have an Internet-Draft
(that is posted and never published as an RFC) or a document from
another standards body, industry consortium, university site, etc.
The expert may provide more in-depth reviews, but their approval
should not be taken as an endorsement of the certificate type.
    

Note

If the "Recommended" column is set to "N", it does not necessarily 
mean that it is flawed; rather, it indicates that the item either 
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.
    

Note

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.
    

Available Formats

CSV

TLS Certificate Status Types

Registration Procedure(s)

IETF Review

Reference

[RFC 6961][RFC 9846][RFC 9851][RFC 9847]

Note

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.
    

Available Formats

CSV

TLS Application-Layer Protocol Negotiation (ALPN) Protocol IDs

Registration Procedure(s)

Expert Review

Expert(s)

Yoav Nir, Rich Salz, Nick Sullivan

Reference

[RFC 7301][RFC 8447][RFC 9847]

Note

Registration requests 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 
[RFC 8447, Section 17] and track its progress.
    

Note

When this registry has an HTTP-specific version added or modified,
the YANG module [iana-http-versions] must be updated as defined
in [RFC-ietf-netconf-http-client-server-31].
    

Available Formats

CSV

TLS CachedInformationType Values

Expert(s)

Yoav Nir, Rich Salz, Nick Sullivan

Reference

[RFC 7924][RFC 9851][RFC 9847]

Note

Requests for registration in the "Specification Required" [RFC 8126] 
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 
[RFC 8447, Section 17] and track its progress. See the registration 
procedure table below for more information.
    

Note

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.
    

Available Formats

CSV

TLS Certificate Compression Algorithm IDs

Expert(s)

Yoav Nir, Rich Salz, Nick Sullivan

Reference

[RFC 8879][RFC 9851][RFC 9847]

Note

Requests for registration in the "Specification Required" [RFC 8126] 
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 
[RFC 8447, Section 17] and track its progress. See the registration 
procedure table below for more information.
    

Note

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.
    

Available Formats

CSV