TLS WG J. Salowey
Internet-Draft Tableau Software
Updates: 3749, 5077, 4680, 5246, 5878, S. Turner
6520, 7301 (if approved) sn3rd
Intended status: Standards Track April 28, 2017
Expires: October 30, 2017

D/TLS IANA Registry Updates


This document changes the IANA registry policy for a number of registries related to DTLS and TLS, renames some of the registries for consistency, and adds notes to many of the registries. As a result, this document updates many RFCs (see updates header).

Status of This Memo

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Table of Contents

1. Process Note

As the authors of this draft are also the WG chairs, the responsible Area Director has agreed to judge consensus.

RFC EDITOR: Please delete section prior to publication.

2. Introduction

This document requests that IANA make changes to a number of DTLS- and TLS-related IANA registries.

In this document, we use the term “(D)TLS” to refer to registries that apply to both TLS and DTLS.

This document proposes no changes to the registration policies for TLS Alert [I-D.ietf-tls-tls13], TLS ContentType [I-D.ietf-tls-tls13], TLS HandshakeType, [I-D.ietf-tls-tls13] and TLS Certificate Status Types [RFC6961]; the existing policies (Standards Action for the first three; IETF Review for the last), are appropriate for these one-byte code points because of their scarcity.

3. Add “TLS” to Registry Names

IANA is to update the names of the following registries to add “TLS” to for consistency with the other TLS-related extensions:

IANA is also to add a reference to this document for the registry whose names have been updated as a result of the above change. The remainder of this document will use the registry names with the “TLS” prefix.

4. Aligning with RFC 5226

Many of the TLS-related IANA registries were defined prior to [RFC5226] where “IETF Consensus” was used instead of the RFC5226-defined “IETF Review”. To align with the new terminology, IANA is to update to use “IETF Review” in place of “IETF Consensus” in the following registries:

This is not a universal change as some registries originally defined with “IETF Consensus” are undergoing other changes either as a result of this document or [I-D.ietf-tls-rfc4492bis].

5. Session Ticket TLS Extension

The nomenclature for the registry entries in the TLS ExtensionType Values registry correspond to the presentation language field name except for entry 35. To ensure that the values in the registry are consistently identified in the registry, IANA is to rename entry 35 to “session_ticket (renamed from “SessionTicket TLS”)”.

6. TLS ExtensionType Values

IANA is to update the TLS ExtensionType Values registry as follows:

Extension Recommended
server_name Yes
max_fragment_length Yes
client_certificate_url Yes
trusted_ca_keys Yes
truncated_hmac Yes
status_request Yes
user_mapping Yes
client_authz No
server_authz No
cert_type Yes
supported_groups Yes
ec_point_formats Yes
srp No
signature_algorithms Yes
use_srtp Yes
heartbeat Yes
application_layer_protocol_negotiation Yes
status_request_v2 Yes
signed_certificate_timestamp No
client_certificate_type Yes
server_certificate_type Yes
padding Yes
encrypt_then_mac Yes
extended_master_secret Yes
session_ticket Yes
renegotiation_info Yes

7. TLS Cipher Suite Registry

IANA is to update the TLS Cipher Suite registry as follows:

The cipher suites that follow are standards track server-authenticated (and optionally client-authenticated) cipher suites which are currently available in TLS 1.2. The notable exception are the ECDHE AES GCM cipher suites which are not yet standards track prior to the publication of this specification, but this document promotes those 4 cipher suites to standards track (see TO-DO insert reference).

RFC EDITOR: Please delete the sentence beginning with “The notable exception …” after RFC 5289 has been promoted to Proposed Standard.

Cipher Suite Name                             | Value
TLS_DHE_RSA_WITH_AES_128_GCM_SHA256           | {0x00,0x9E}
TLS_DHE_RSA_WITH_AES_256_GCM_SHA384           | {0x00,0x9F}
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256       | {0xC0,0x2B}
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384       | {0xC0,0x2C}
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256         | {0xC0,0x2F}
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384         | {0xC0,0x30}
TLS_DHE_RSA_WITH_AES_128_CCM                  | {0xC0,0x9E}
TLS_DHE_RSA_WITH_AES_256_CCM                  | {0xC0,0x9F}
TLS_DHE_RSA_WITH_AES_128_CCM_8                | {0xC0,0xA2}
TLS_DHE_RSA_WITH_AES_256_CCM_8                | {0xC0,0xA3}

The cipher suites that follow are standards track ephemeral pre-shared key cipher suites which are available in TLS 1.2. [RFC6655] is inconsistent with respect to the ordering of components within PSK AES CCM cipher suite names; those names are used here without modification.

Cipher Suite Name                             | Value
TLS_DHE_PSK_WITH_AES_128_GCM_SHA256           | {0x00,0xAA}
TLS_DHE_PSK_WITH_AES_256_GCM_SHA384           | {0x00,0xAB}
TLS_DHE_PSK_WITH_AES_128_CCM                  | {0xC0,0xA6}
TLS_DHE_PSK_WITH_AES_256_CCM                  | {0xC0,0xA7}
TLS_PSK_DHE_WITH_AES_128_CCM_8                | {0xC0,0xAA}
TLS_PSK_DHE_WITH_AES_256_CCM_8                | {0xC0,0xAB}

8. TLS Supported Groups

Add a “Recommended” column with a “Yes” for secp256r1, secp384r1, x25519, and x448 while all others are “No”. These “Yes” groups are taken from Standards Track RFCs. Not all groups from [I-D.ietf-tls-rfc4492bis], which is standards track, are not marked as “Yes”; these groups apply to TLS 1.3 [I-D.ietf-tls-tls13] and previous versions of TLS [I-D.ietf-tls-tls13]. A Standards Track document [RFC5226] is required to register an entry with the value “Yes”.

9. TLS ClientCertificateType Identifiers

IANA is to update the TLS ClientCertificateType Identifiers registry as follows:

10. New Session Ticket TLS Handshake Message Type

To align with TLS implementations and to align the naming nomenclature for other Handshake message types, IANA is to rename entry 4 in the TLS HandshakeType registry to “new_session_ticket (renamed from NewSessionTicket)”. IANA is to also add a reference to this document in the Reference column for entry 4 in the TLS HandshakeType registry.

11. TLS Exporter Label Registry

IANA is to add the following note to the TLS Exporter Label Registry:

Note: {{RFC5705}} defines keying material exporters for TLS in terms of the TLS PRF. {{I-D.ietf-tls-tls13}} replaced the PRF with HKDF, thus requiring a new construction. The exporter interface remains the same, however the value is computed different.

IANA is to also to add a “Recommended” column to the TLS Exporter Label registry. The table that follows has been generated by marking Standards Track RFCs as “Yes” and all others as “No”. Future exporters MUST define the value of this column. A Standards Track document [RFC5226] is required to register an extension with the value “Yes”.

IANA is also to add the following note:

Note: The designated expert {{RFC5226}} ensures that the specification is publicly available.  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.
Exporter Value
client finished
server finished
master secret
key expansion
client EAP encryption
ttls keying material
ttls challenge
EXPORTER: teap session key seed

12. Add Missing Item to TLS Alert Registry

IANA is to add the following entry to the TLS Alert Registry (the entry was omitted from the IANA instructions in [RFC7301]):

120   no_application_protocol  Y  [RFC7301]

13. TLS Certificate Types

Add a “Recommended” column to the registry. X.509 and Raw Public Key are “Yes”. All others are “No”. A Standards Track document [RFC5226] is required to register a certificate type with the value “Yes”.

14. Orphaned Extensions

To make it clear that (D)TLS 1.3 has orphaned certain extensions (i.e., they are only applicable to version of (D)TLS prior to 1.3), IANA is to add the following to the TLS ExtensionType Values registry:

Note: The following extensions are only applicable to (D)TLS protocol vesions prior to 1.3: trusted_ca_keys, truncated_hmac, ec_point_formats, srp, status_request_v2, encrypt_then_mac, extended_master_secret, session_ticket, and renegotiation_info. These are not applicable to DTLS 1.3.

15. Orphaned Registries

To make it clear that (D)TLS 1.3 has orphaned certain registries (i.e., they are only applicable to version of (D)TLS protocol versions prior to 1.3), IANA is to:

IANA [SHALL update/has updated] the TLS HashAlgorithm Registry to list values 7-223 as “Reserved” and the TLS SignatureAlgorithm registry to list values 4-223 as “Reserved”.

16. Designated Expert Pool

Specification Required [RFC5226] registry requests are registered after a three-week review period on the (tbd but maybe mailing list, 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.

Registration requests sent to the mailing list for review SHOULD use an appropriate subject (e.g., “Request to register value in TLS bar registry”).

Within the review period, the Designated Experts will either approve or deny the registration request, communicating this decision to the review list and IANA. Denials SHOULD include an explanation and, if applicable, suggestions as to how to make the request successful. Registration requests that are undetermined for a period longer than 21 days can be brought to the IESG’s attention (using the mailing list) for resolution.

Criteria that SHOULD be applied by the Designated Experts includes determining whether the proposed registration duplicates existing functionality, whether it is likely to be of general applicability or useful only for a single application, and whether the registration description is clear.

IANA MUST only accept registry updates from the Designated Experts and SHOULD direct all requests for registration to the review mailing list.

It is suggested that multiple Designated Experts be appointed who are able to represent the perspectives of different applications using this specification, in order to enable broadly informed review of registration decisions. In cases where a registration decision could be perceived as creating a conflict of interest for a particular Expert, that Expert SHOULD defer to the judgment of the other Experts.

17. Security Considerations

The authors are fairly certain that there are no security considerations for this document.

18. IANA Considerations

This document is entirely about changes to TLS-related IANA registries.

19. References

19.1. Normative References

[I-D.ietf-tls-tls13] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", Internet-Draft draft-ietf-tls-tls13-19, March 2017.
[RFC3749] Hollenbeck, S., "Transport Layer Security Protocol Compression Methods", RFC 3749, DOI 10.17487/RFC3749, May 2004.
[RFC4680] Santesson, S., "TLS Handshake Message for Supplemental Data", RFC 4680, DOI 10.17487/RFC4680, October 2006.
[RFC5077] Salowey, J., Zhou, H., Eronen, P. and H. Tschofenig, "Transport Layer Security (TLS) Session Resumption without Server-Side State", RFC 5077, DOI 10.17487/RFC5077, January 2008.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, DOI 10.17487/RFC5226, May 2008.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/RFC5246, August 2008.
[RFC5705] Rescorla, E., "Keying Material Exporters for Transport Layer Security (TLS)", RFC 5705, DOI 10.17487/RFC5705, March 2010.
[RFC5878] Brown, M. and R. Housley, "Transport Layer Security (TLS) Authorization Extensions", RFC 5878, DOI 10.17487/RFC5878, May 2010.
[RFC6520] Seggelmann, R., Tuexen, M. and M. Williams, "Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS) Heartbeat Extension", RFC 6520, DOI 10.17487/RFC6520, February 2012.
[RFC6655] McGrew, D. and D. Bailey, "AES-CCM Cipher Suites for Transport Layer Security (TLS)", RFC 6655, DOI 10.17487/RFC6655, July 2012.
[RFC7301] Friedl, S., Popov, A., Langley, A. and E. Stephan, "Transport Layer Security (TLS) Application-Layer Protocol Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301, July 2014.

19.2. Informative References

[I-D.ietf-tls-rfc4492bis] Nir, Y., Josefsson, S. and M. Pegourie-Gonnard, "Elliptic Curve Cryptography (ECC) Cipher Suites for Transport Layer Security (TLS) Versions 1.2 and Earlier", Internet-Draft draft-ietf-tls-rfc4492bis-16, March 2017.
[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", RFC 2434, DOI 10.17487/RFC2434, October 1998.
[RFC6961] Pettersen, Y., "The Transport Layer Security (TLS) Multiple Certificate Status Request Extension", RFC 6961, DOI 10.17487/RFC6961, June 2013.

Authors' Addresses

Joe Salowey Tableau Software EMail:
Sean Turner sn3rd EMail: