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rfc:rfc8447

Internet Engineering Task Force (IETF) J. Salowey Request for Comments: 8447 Tableau Software Updates: 3749, 5077, 4680, 5246, 5705, S. Turner

       5878, 6520, 7301                                          sn3rd

Category: Standards Track August 2018 ISSN: 2070-1721

               IANA Registry Updates for TLS and DTLS

Abstract

 This document describes a number of changes to TLS and DTLS IANA
 registries that range from adding notes to the registry all the way
 to changing the registration policy.  These changes were mostly
 motivated by WG review of the TLS- and DTLS-related registries
 undertaken as part of the TLS 1.3 development process.
 This document updates the following RFCs: 3749, 5077, 4680, 5246,
 5705, 5878, 6520, and 7301.

Status of This Memo

 This is an Internet Standards Track document.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 Internet Standards is available in Section 2 of RFC 7841.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 https://www.rfc-editor.org/info/rfc8447.

Salowey & Turner Standards Track [Page 1] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

Copyright Notice

 Copyright (c) 2018 IETF Trust and the persons identified as the
 document authors.  All rights reserved.
 This document is subject to BCP 78 and the IETF Trust's Legal
 Provisions Relating to IETF Documents
 (https://trustee.ietf.org/license-info) in effect on the date of
 publication of this document.  Please review these documents
 carefully, as they describe your rights and restrictions with respect
 to this document.  Code Components extracted from this document must
 include Simplified BSD License text as described in Section 4.e of
 the Trust Legal Provisions and are provided without warranty as
 described in the Simplified BSD License.

Table of Contents

 1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
 2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
 3.  Adding "TLS" to Registry Names  . . . . . . . . . . . . . . .   3
 4.  Aligning with RFC 8126  . . . . . . . . . . . . . . . . . . .   4
 5.  Adding "Recommended" Column . . . . . . . . . . . . . . . . .   4
 6.  Session Ticket TLS Extension  . . . . . . . . . . . . . . . .   4
 7.  TLS ExtensionType Values  . . . . . . . . . . . . . . . . . .   5
 8.  TLS Cipher Suites Registry  . . . . . . . . . . . . . . . . .   8
 9.  TLS Supported Groups  . . . . . . . . . . . . . . . . . . . .  10
 10. TLS ClientCertificateType Identifiers . . . . . . . . . . . .  11
 11. New Session Ticket TLS Handshake Message Type . . . . . . . .  12
 12. TLS Exporter Labels Registry  . . . . . . . . . . . . . . . .  12
 13. Adding Missing Item to TLS Alerts Registry  . . . . . . . . .  13
 14. TLS Certificate Types . . . . . . . . . . . . . . . . . . . .  14
 15. Orphaned Registries . . . . . . . . . . . . . . . . . . . . .  15
 16. Additional Notes  . . . . . . . . . . . . . . . . . . . . . .  16
 17. Designated Expert Pool  . . . . . . . . . . . . . . . . . . .  16
 18. Security Considerations . . . . . . . . . . . . . . . . . . .  17
 19. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  18
 20. References  . . . . . . . . . . . . . . . . . . . . . . . . .  18
   20.1.  Normative References . . . . . . . . . . . . . . . . . .  18
   20.2.  Informative References . . . . . . . . . . . . . . . . .  19
 Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  20

Salowey & Turner Standards Track [Page 2] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

1. Introduction

 Per this document, IANA has made changes to a number of IANA
 registries related to Transport Layer Security (TLS) and Datagram
 Transport Layer Security (DTLS).  These changes were almost entirely
 motivated by the development of TLS 1.3 [RFC8446].
 The changes introduced by this document range from simple, e.g.,
 adding notes, to complex, e.g., changing a registry's registration
 policy.  Instead of listing the changes and their rationale here in
 the introduction, each section provides rationale for the proposed
 change(s).
 This document proposes no changes to the registration policies for
 TLS Alerts [RFC8446], TLS ContentType [RFC8446], TLS HandshakeType
 [RFC8446], and TLS Certificate Status Types [RFC6961] registries; 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.

2. Terminology

 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
 "OPTIONAL" in this document are to be interpreted as described in
 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
 capitals, as shown here.

3. Adding "TLS" to Registry Names

 For consistency amongst TLS registries, IANA has prepended "TLS" to
 the following registries:
 o  Application-Layer Protocol Negotiation (ALPN) Protocol IDs
    [RFC7301],
 o  ExtensionType Values,
 o  Heartbeat Message Types [RFC6520], and
 o  Heartbeat Modes [RFC6520].
 IANA has updated the reference for these four registries to also
 refer to this document.  The remainder of this document will use the
 registry names with the "TLS" prefix.

Salowey & Turner Standards Track [Page 3] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

4. Aligning with RFC 8126

 Many of the TLS-related IANA registries had the registration
 procedure "IETF Consensus", which was changed to "IETF Review" by
 [RFC8126].  To align with the new terminology, IANA has updated the
 following registries to "IETF Review":
 o  TLS Authorization Data Formats [RFC4680]
 o  TLS Supplemental Data Formats (SupplementalDataType) [RFC5878]
 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, [RFC8446], or [RFC8422].
 IANA has updated the reference for these two registries to also refer
 to this document.

5. Adding "Recommended" Column

 Per this document, a "Recommended" column has been added to many of
 the TLS registries to indicate parameters that are generally
 recommended for implementations to support.  Adding a "Recommended"
 parameter (i.e., "Y") to a registry or updating a parameter to
 "Recommended" status requires Standards Action.  Not all parameters
 defined in Standards Track documents need to be marked as
 "Recommended".
 If an item is not marked as "Recommended" (i.e., "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.

6. 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:
 o  has renamed entry 35 to "session_ticket (renamed from
    "SessionTicket TLS")" [RFC5077].
 o  has added a reference to this document in the "Reference" column
    for entry 35.

Salowey & Turner Standards Track [Page 4] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

7. TLS ExtensionType Values

 Experience has shown that the IETF Review registry policy for TLS
 extensions was too strict.  Based on WG consensus, the decision was
 taken to change the registration policy to Specification Required
 [RFC8126] while reserving a small part of the code space for private
 use.  Therefore, IANA has updated the TLS ExtensionType Values
 registry as follows:
 o  Changed the registry policy to:
    Values with the first byte in the range 0-254 (decimal) are
    assigned via Specification Required [RFC8126].  Values with the
    first byte 255 (decimal) are reserved for Private Use [RFC8126].
 o  Updated the "Reference" to also refer to this document.
 See Section 17 for additional information about the designated expert
 pool.
 Despite wanting to "loosen" the registration policies for TLS
 extensions, it is still useful to indicate in the IANA registry which
 extensions the WG recommends be supported.  Therefore, IANA has
 updated the TLS ExtensionType Values registry as follows:
 o  Added a "Recommended" column with the contents as listed below.
    This table has been generated by marking Standards Track RFCs as
    "Y" and all others as "N".  The "Recommended" column is assigned a
    value of "N" unless explicitly requested, and adding a value with
    a "Recommended" value of "Y" requires Standards Action [RFC8126].
    IESG Approval is REQUIRED for a Y->N transition.
       +----------------------------------------+-------------+
       | Extension                              | Recommended |
       +----------------------------------------+-------------+
       | server_name                            |           Y |
       |                                        |             |
       | max_fragment_length                    |           N |
       |                                        |             |
       | client_certificate_url                 |           Y |
       |                                        |             |
       | trusted_ca_keys                        |           Y |
       |                                        |             |
       | truncated_hmac                         |           Y |
       |                                        |             |
       | status_request                         |           Y |
       |                                        |             |
       | user_mapping                           |           Y |

Salowey & Turner Standards Track [Page 5] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

       +----------------------------------------+-------------+
       | Extension                              | Recommended |
       +----------------------------------------+-------------+
       | client_authz                           |           N |
       |                                        |             |
       | server_authz                           |           N |
       |                                        |             |
       | cert_type                              |           N |
       |                                        |             |
       | supported_groups                       |           Y |
       |                                        |             |
       | ec_point_formats                       |           Y |
       |                                        |             |
       | srp                                    |           N |
       |                                        |             |
       | signature_algorithms                   |           Y |
       |                                        |             |
       | use_srtp                               |           Y |
       |                                        |             |
       | heartbeat                              |           Y |
       |                                        |             |
       | application_layer_protocol_negotiation |           Y |
       |                                        |             |
       | status_request_v2                      |           Y |
       |                                        |             |
       | signed_certificate_timestamp           |           N |
       |                                        |             |
       | client_certificate_type                |           Y |
       |                                        |             |
       | server_certificate_type                |           Y |
       |                                        |             |
       | padding                                |           Y |
       |                                        |             |
       | encrypt_then_mac                       |           Y |
       |                                        |             |
       | extended_master_secret                 |           Y |
       |                                        |             |
       | cached_info                            |           Y |
       |                                        |             |
       | session_ticket                         |           Y |
       |                                        |             |
       | renegotiation_info                     |           Y |
       +----------------------------------------+-------------+

Salowey & Turner Standards Track [Page 6] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

 IANA has added the following notes:
 Note:  The role of the designated expert is described in RFC 8447.
    The designated expert [RFC8126] 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 [RFC8126], 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 an item is not marked as "Recommended", 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.
 The extensions added by [RFC8446] are omitted from the above table;
 additionally, token_binding is omitted, since [TOKBIND] specifies the
 value of the "Recommended" column for this extension.
 [RFC8446] also uses the TLS ExtensionType Values registry originally
 created in [RFC4366].  The following text is from [RFC8446] and is
 included here to ensure alignment between these specifications.
 o  IANA has updated this registry to include the "key_share",
    "pre_shared_key", "psk_key_exchange_modes", "early_data",
    "cookie", "supported_versions", "certificate_authorities",
    "oid_filters", "post_handshake_auth", and
    "signature_algorithms_cert" extensions with the values defined in
    [RFC8446] and the "Recommended" value of "Y".
 o  IANA has updated this registry to include a "TLS 1.3" column that
    lists the messages in which the extension may appear.  This column
    has been initially populated from the table in Section 4.2 of
    [RFC8446] with any extension not listed there marked as "-" to
    indicate that it is not used by TLS 1.3.

Salowey & Turner Standards Track [Page 7] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

8. TLS Cipher Suites Registry

 Experience has shown that the IETF Consensus registry policy for TLS
 Cipher Suites was too strict.  Based on WG consensus, the decision
 was taken to change the TLS Cipher Suites registry's registration
 policy to Specification Required [RFC8126] while reserving a small
 part of the code space for private use.  Therefore, IANA has updated
 the TLS Cipher Suites registry's policy as follows:
    Values with the first byte in the range 0-254 (decimal) are
    assigned via Specification Required [RFC8126].  Values with the
    first byte 255 (decimal) are reserved for Private Use [RFC8126].
 See Section 17 for additional information about the designated expert
 pool.
 The TLS Cipher Suites registry has grown significantly and will
 continue to do so.  To better guide those not intimately involved in
 TLS, IANA has updated the TLS Cipher Suites registry as follows:
 o  Added a "Recommended" column to the TLS Cipher Suites registry.
    The cipher suites that follow in the two tables are marked as "Y".
    All other cipher suites are marked as "N".  The "Recommended"
    column is assigned a value of "N" unless explicitly requested, and
    adding a value with a "Recommended" value of "Y" requires
    Standards Action [RFC8126].  IESG Approval is REQUIRED for a Y->N
    transition.
 The cipher suites that follow are Standards Track server-
 authenticated (and optionally client-authenticated) cipher suites
 that are currently available in TLS 1.2.
 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_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256   | {0xCC,0xA8}
 TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256 | {0xCC,0xA9}
 TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256     | {0xCC,0xAA}

Salowey & Turner Standards Track [Page 8] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

 The cipher suites that follow are Standards Track ephemeral pre-
 shared key cipher suites that are available in TLS 1.2.
 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_ECDHE_PSK_WITH_AES_128_GCM_SHA256         | {0xD0,0x01}
 TLS_ECDHE_PSK_WITH_AES_256_GCM_SHA384         | {0xD0,0x02}
 TLS_ECDHE_PSK_WITH_AES_128_CCM_SHA256         | {0xD0,0x05}
 TLS_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256   | {0xCC,0xAC}
 TLS_DHE_PSK_WITH_CHACHA20_POLY1305_SHA256     | {0xCC,0xAD}
 The TLS 1.3 cipher suites specified by [RFC8446] are not listed here;
 that document provides for their "Recommended" status.
 Despite the following behavior being misguided, experience has shown
 that some customers use the IANA registry as a checklist against
 which to measure an implementation's completeness, and some
 implementers blindly implement cipher suites.  Therefore, IANA has
 added the following warning to the registry:
 WARNING:  Cryptographic algorithms and parameters will be broken or
    weakened over time.  Blindly implementing cipher suites listed
    here is not advised.  Implementers and users need to check that
    the cryptographic algorithms listed continue to provide the
    expected level of security.
 IANA has added the following note to ensure that those that focus on
 IANA registries are aware that TLS 1.3 [RFC8446] uses the same
 registry but defines ciphers differently:
 Note:  Although TLS 1.3 uses the same cipher suite space as previous
    versions of TLS, TLS 1.3 cipher suites are defined differently,
    only specifying the symmetric ciphers and hash function, and
    cannot be used for TLS 1.2.  Similarly, TLS 1.2 and lower cipher
    suite values cannot be used with TLS 1.3.
 IANA has added the following notes to document the rules for
 populating the "Recommended" column:
 Note:  CCM_8 cipher suites are not marked as "Recommended".  These
    cipher suites have a significantly truncated authentication tag
    that represents a security trade-off that may not be appropriate
    for general environments.

Salowey & Turner Standards Track [Page 9] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

 Note:  If an item is not marked as "Recommended", 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.
 IANA has added the following notes for additional information:
 Note:  The role of the designated expert is described in RFC 8447.
    The designated expert [RFC8126] 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 cipher suite.
 Note:  As specified in [RFC8126], 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.
 IANA has updated the reference for this registry to also refer to
 this document.

9. TLS Supported Groups

 Similar to cipher suites, supported groups have proliferated over
 time, and some use the registry to measure implementations.
 Therefore, IANA has added a "Recommended" column with a "Y" for
 secp256r1, secp384r1, x25519, and x448, while all others are "N".
 These "Y" groups are taken from Standards Track RFCs; [RFC8422]
 elevates secp256r1 and secp384r1 to Standards Track.  Not all groups
 from [RFC8422], which is Standards Track, are marked as "Y"; these
 groups apply to TLS 1.3 [RFC8446] and previous versions of TLS.  The
 "Recommended" column is assigned a value of "N" unless explicitly
 requested, and adding a value with a "Recommended" value of "Y"
 requires Standards Action [RFC8126].  IESG Approval is REQUIRED for a
 Y->N transition.
 IANA has added the following notes:
 Note:  If an item is not marked as "Recommended", 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.

Salowey & Turner Standards Track [Page 10] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

 Note:  The role of the designated expert is described in RFC 8447.
    The designated expert [RFC8126] 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 supported group.
 Despite the following behavior being misguided, experience has shown
 that some customers use the IANA registry as a checklist against
 which to measure an implementation's completeness, and some
 implementers blindly implement supported groups.  Therefore, IANA has
 added the following warning to the registry:
 WARNING:  Cryptographic algorithms and parameters will be broken or
    weakened over time.  Blindly implementing supported groups listed
    here is not advised.  Implementers and users need to check that
    the cryptographic algorithms listed continue to provide the
    expected level of security.
 IANA has updated the reference for this registry to also refer to
 this document.
 The value 0 (0x0000) has been marked as reserved.

10. TLS ClientCertificateType Identifiers

 Experience has shown that the IETF Consensus registry policy for TLS
 ClientCertificateType Identifiers is too strict.  Based on WG
 consensus, the decision was taken to change the registration policy
 to Specification Required [RFC8126] while reserving some of the code
 space for Standards Track usage and a small part of the code space
 for private use.  Therefore, IANA has updated the TLS
 ClientCertificateType Identifiers registry's policy as follows:
    Values in the range 0-63 are assigned via Standards Action.
    Values 64-223 are assigned via Specification Required [RFC8126].
    Values 224-255 are reserved for Private Use.
 See Section 17 for additional information about the designated expert
 pool.

Salowey & Turner Standards Track [Page 11] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

 IANA has added the following notes:
 Note:  The role of the designated expert is described in RFC 8447.
    The designated expert [RFC8126] 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 identifier.
 Note:  As specified in [RFC8126], 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.

11. New Session Ticket TLS Handshake Message Type

 To align with TLS implementations and to align the naming
 nomenclature with other Handshake message types, IANA:
 o  has renamed entry 4 in the TLS HandshakeType registry to
    "new_session_ticket (renamed from NewSessionTicket)" [RFC5077].
 o  has added a reference to this document in the "Reference" column
    for entry 4 in the TLS HandshakeType registry.

12. TLS Exporter Labels Registry

 To aid those reviewers who start with the IANA registry, IANA has
 added:
 o  The following note to the TLS Exporter Labels registry:
 Note:  [RFC5705] defines keying material exporters for TLS in terms
    of the TLS PRF.  [RFC8446] replaced the PRF with HKDF, thus
    requiring a new construction.  The exporter interface remains the
    same; however, the value is computed differently.
 o  A "Recommended" column to the TLS Exporter Labels registry.  The
    table that follows has been generated by marking Standards Track
    RFCs as "Y" and all others as "N".  The "Recommended" column is
    assigned a value of "N" unless explicitly requested, and adding a
    value with a "Recommended" value of "Y" requires Standards Action
    [RFC8126].  IESG Approval is REQUIRED for a Y->N transition.

Salowey & Turner Standards Track [Page 12] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

    Exporter Value                  | Recommended |
    --------------------------------|-------------|
    client finished                 |           Y |
    server finished                 |           Y |
    master secret                   |           Y |
    key expansion                   |           Y |
    client EAP encryption           |           Y |
    ttls keying material            |           N |
    ttls challenge                  |           N |
    EXTRACTOR-dtls_srtp             |           Y |
    EXPORTER_DTLS_OVER_SCTP         |           Y |
    EXPORTER: teap session key seed |           Y |
 To provide additional information for the designated experts, IANA
 has added the following notes:
 Note:  The role of the designated expert is described in RFC 8447.
    The designated expert [RFC8126] 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 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.
 Note:  If an item is not marked as "Recommended", 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.
 IANA has updated the reference for this registry to also refer to
 this document.

13. Adding Missing Item to TLS Alerts Registry

 IANA has added the following entry to the TLS Alerts registry; the
 entry was omitted from the IANA instructions in [RFC7301]:
 120   no_application_protocol  Y  [RFC7301] [RFC8447]

Salowey & Turner Standards Track [Page 13] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

14. TLS Certificate Types

 Experience has shown that the IETF Consensus registry policy for TLS
 Certificate Types is too strict.  Based on WG consensus, the decision
 was taken to change registration policy to Specification Required
 [RFC8126] while reserving a small part of the code space for private
 use.  Therefore, IANA has changed the TLS Certificate Types registry
 as follows:
 o  Changed the registry policy to:
    Values in the range 0-223 (decimal) are assigned via Specification
    Required [RFC8126].  Values in the range 224-255 (decimal) are
    reserved for Private Use [RFC8126].
 o  Added a "Recommended" column to the registry.  X.509 and Raw
    Public Key are "Y".  All others are "N".  The "Recommended" column
    is assigned a value of "N" unless explicitly requested, and adding
    a value with a "Recommended" value of "Y" requires Standards
    Action [RFC8126].  IESG Approval is REQUIRED for a Y->N
    transition.
 See Section 17 for additional information about the designated expert
 pool.
 IANA has added the following notes:
 Note:  The role of the designated expert is described in RFC 8447.
    The designated expert [RFC8126] 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 an item is not marked as "Recommended", 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.
 IANA has updated the reference for this registry to also refer this
 document.

Salowey & Turner Standards Track [Page 14] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

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:
 o  has added the following to the TLS Compression Method Identifiers
    registry [RFC3749]:
 Note:  Value 0 (NULL) is the only value in this registry applicable
    to (D)TLS protocol version 1.3 or later.
 o  has added the following to the TLS HashAlgorithm [RFC5246] and TLS
    SignatureAlgorithm registries [RFC5246]:
 Note:  The values in this registry are only applicable to (D)TLS
    protocol versions prior to 1.3.  (D)TLS 1.3 and later versions'
    values are registered in the TLS SignatureScheme registry.
 o  has updated the "Reference" field in the TLS Compression Method
    Identifiers, TLS HashAlgorithm and TLS SignatureAlgorithm
    registries to also refer to this document.
 o  has updated the TLS HashAlgorithm registry to list values 7 and
    9-223 as "Reserved" and the TLS SignatureAlgorithm registry to
    list values 4-6 and 9-223 as "Reserved".
 o  has added the following to the TLS ClientCertificateType
    Identifiers registry [RFC5246]:
 Note:  The values in this registry are only applicable to (D)TLS
    protocol versions prior to 1.3.
 Despite the fact that the TLS HashAlgorithm and SignatureAlgorithm
 registries are orphaned, it is still important to warn implementers
 of pre-TLS1.3 implementations about the dangers of blindly
 implementing cryptographic algorithms.  Therefore, IANA has added the
 following warning to the TLS HashAlgorithm and SignatureAlgorithm
 registries:
 WARNING:  Cryptographic algorithms and parameters will be broken or
    weakened over time.  Blindly implementing the cryptographic
    algorithms listed here is not advised.  Implementers and users
    need to check that the cryptographic algorithms listed continue to
    provide the expected level of security.

Salowey & Turner Standards Track [Page 15] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

16. Additional Notes

 IANA has added the following warning and note to the TLS
 SignatureScheme registry:
 WARNING:  Cryptographic algorithms and parameters will be broken or
    weakened over time.  Blindly implementing signature schemes listed
    here is not advised.  Implementers and users need to check that
    the cryptographic algorithms listed continue to provide the
    expected level of security.
 Note:  As specified in [RFC8126], 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.
 IANA has added the following notes to the TLS PskKeyExchangeMode
 registry:
 Note:  If an item is not marked as "Recommended", 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.
 Note:  The role of the designated expert is described in RFC 8447.
    The designated expert [RFC8126] 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 key exchange mode.

17. Designated Expert Pool

 Specification Required [RFC8126] registry requests are registered
 after a three-week review period on the <tls-reg-review@ietf.org>
 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").

Salowey & Turner Standards Track [Page 16] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

 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
 <iesg@ietf.org> 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.

18. Security Considerations

 The change to Specification Required from IETF Review lowers the
 amount of review provided by the WG for cipher suites and supported
 groups.  This change reflects reality in that the WG essentially
 provided no cryptographic review of the cipher suites or supported
 groups.  This was especially true of national cipher suites.
 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.

Salowey & Turner Standards Track [Page 17] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

19. IANA Considerations

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

20. References

20.1. Normative References

 [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
            Requirement Levels", BCP 14, RFC 2119,
            DOI 10.17487/RFC2119, March 1997,
            <https://www.rfc-editor.org/info/rfc2119>.
 [RFC3749]  Hollenbeck, S., "Transport Layer Security Protocol
            Compression Methods", RFC 3749, DOI 10.17487/RFC3749, May
            2004, <https://www.rfc-editor.org/info/rfc3749>.
 [RFC4680]  Santesson, S., "TLS Handshake Message for Supplemental
            Data", RFC 4680, DOI 10.17487/RFC4680, October 2006,
            <https://www.rfc-editor.org/info/rfc4680>.
 [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, <https://www.rfc-editor.org/info/rfc5077>.
 [RFC5246]  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/info/rfc5246>.
 [RFC5705]  Rescorla, E., "Keying Material Exporters for Transport
            Layer Security (TLS)", RFC 5705, DOI 10.17487/RFC5705,
            March 2010, <https://www.rfc-editor.org/info/rfc5705>.
 [RFC5878]  Brown, M. and R. Housley, "Transport Layer Security (TLS)
            Authorization Extensions", RFC 5878, DOI 10.17487/RFC5878,
            May 2010, <https://www.rfc-editor.org/info/rfc5878>.
 [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,
            <https://www.rfc-editor.org/info/rfc6520>.

Salowey & Turner Standards Track [Page 18] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

 [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, <https://www.rfc-editor.org/info/rfc7301>.
 [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
            Writing an IANA Considerations Section in RFCs", BCP 26,
            RFC 8126, DOI 10.17487/RFC8126, June 2017,
            <https://www.rfc-editor.org/info/rfc8126>.
 [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
            2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
            May 2017, <https://www.rfc-editor.org/info/rfc8174>.
 [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
            Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
            <https://www.rfc-editor.org/info/rfc8446>.

20.2. Informative References

 [RFC4366]  Blake-Wilson, S., Nystrom, M., Hopwood, D., Mikkelsen, J.,
            and T. Wright, "Transport Layer Security (TLS)
            Extensions", RFC 4366, DOI 10.17487/RFC4366, April 2006,
            <https://www.rfc-editor.org/info/rfc4366>.
 [RFC6961]  Pettersen, Y., "The Transport Layer Security (TLS)
            Multiple Certificate Status Request Extension", RFC 6961,
            DOI 10.17487/RFC6961, June 2013,
            <https://www.rfc-editor.org/info/rfc6961>.
 [RFC8422]  Nir, Y., Josefsson, S., and M. Pegourie-Gonnard, "Elliptic
            Curve Cryptography (ECC) Cipher Suites for Transport Layer
            Security (TLS) Versions 1.2 and Earlier", RFC 8422,
            DOI 10.17487/RFC8422, August 2018,
            <https://www.rfc-editor.org/info/rfc8422>.
 [TOKBIND]  Popov, A., Nystrom, M., Balfanz, D., and A. Langley,
            "Transport Layer Security (TLS) Extension for Token
            Binding Protocol Negotiation", Work in Progress,
            draft-ietf-tokbind-negotiation-14, May 2018.

Salowey & Turner Standards Track [Page 19] RFC 8447 IANA Registry Updates for TLS and DTLS August 2018

Authors' Addresses

 Joe Salowey
 Tableau Software
 Email: joe@salowey.net
 Sean Turner
 sn3rd
 Email: sean@sn3rd.com

Salowey & Turner Standards Track [Page 20]

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