Transport Layer Security (TLS) Extensions

Created

• 2005-11-15

Last Updated

• 2026-10-08

Related Registry Group(s)

Transport Layer Security (TLS) Parameters

Available Formats

• XML
• HTML
• TXT

TLS ExtensionType Values

Expert(s)

• Yoav Nir, Rich Salz, Nick Sullivan

Reference

• RFC 9846: The Transport Layer Security (TLS) Protocol Version 1.3
• RFC 8447: IANA Registry Updates for TLS and DTLS
• RFC 9146: Connection Identifier for DTLS 1.2
• RFC 9851: TLS 1.2 is in Feature Freeze
• RFC 9847: IANA Registry Updates for TLS and DTLS

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: Using OpenPGP Keys for Transport Layer Security (TLS) Authentication
• RFC 9846: The Transport Layer Security (TLS) Protocol Version 1.3
• RFC 8447: IANA Registry Updates for TLS and DTLS
• RFC 9851: TLS 1.2 is in Feature Freeze
• RFC 9847: IANA Registry Updates for TLS and DTLS

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: The Transport Layer Security (TLS) Multiple Certificate Status Request Extension
• RFC 9846: The Transport Layer Security (TLS) Protocol Version 1.3
• RFC 9851: TLS 1.2 is in Feature Freeze
• RFC 9847: IANA Registry Updates for TLS and DTLS

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: Transport Layer Security (TLS) Application-Layer Protocol Negotiation Extension
• RFC 8447: IANA Registry Updates for TLS and DTLS
• RFC 9847: IANA Registry Updates for TLS and DTLS

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: Transport Layer Security (TLS) Cached Information Extension
• RFC 9851: TLS 1.2 is in Feature Freeze
• RFC 9847: IANA Registry Updates for TLS and DTLS

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: TLS Certificate Compression
• RFC 9851: TLS 1.2 is in Feature Freeze
• RFC 9847: IANA Registry Updates for TLS and DTLS

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