IANA Registry Updates for Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)
draft-salowey-tls-rfc8447bis-00
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
|
|
|---|---|---|---|
| Authors | Joseph A. Salowey , Sean Turner | ||
| Last updated | 2021-08-15 | ||
| Replaced by | draft-ietf-tls-rfc8447bis | ||
| RFC stream | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
draft-salowey-tls-rfc8447bis-00
TLS WG J. Salowey
Internet-Draft Salesforce
Obsoletes: 8447 (if approved) S. Turner
Updates: 3749, 5077, 4680, 5246, 5705, 5878, sn3rd
6520, 7301 (if approved) 15 August 2021
Intended status: Standards Track
Expires: 16 February 2022
IANA Registry Updates for Transport Layer Security (TLS) and Datagram
Transport Layer Security (DTLS)
draft-salowey-tls-rfc8447bis-00
Abstract
This document describes a number of changes to (D)TLS 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 (D)TLS-related registries undertaken as part of the
TLS1.3 development process.
This document obsoletes RFC8447 and updates the following RFCs: 3749,
5077, 4680, 5246, 5705, 5878, 6520, 7301.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 16 February 2022.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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 . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Add "TLS" to Registry Names . . . . . . . . . . . . . . . . . 3
4. Aligning with RFC 8126 . . . . . . . . . . . . . . . . . . . 3
5. Adding Recommended Column . . . . . . . . . . . . . . . . . . 4
6. Session Ticket TLS Extension . . . . . . . . . . . . . . . . 4
7. TLS ExtensionType Values . . . . . . . . . . . . . . . . . . 5
8. TLS Cipher Suite Registry . . . . . . . . . . . . . . . . . . 8
9. TLS Supported Groups . . . . . . . . . . . . . . . . . . . . 11
10. TLS ClientCertificateType Identifiers . . . . . . . . . . . . 12
11. New Session Ticket TLS Handshake Message Type . . . . . . . . 13
12. TLS Exporter Label Registry . . . . . . . . . . . . . . . . . 13
13. Add Missing Item to TLS Alert Registry . . . . . . . . . . . 14
14. TLS Certificate Types . . . . . . . . . . . . . . . . . . . . 15
15. Orphaned Extensions . . . . . . . . . . . . . . . . . . . . . 16
16. Orphaned Registries . . . . . . . . . . . . . . . . . . . . . 16
17. Experimental Codepoints . . . . . . . . . . . . . . . . . . . 17
17.1. Extensions . . . . . . . . . . . . . . . . . . . . . . . 18
17.2. Supported Groups . . . . . . . . . . . . . . . . . . . . 18
18. Designated Expert Pool . . . . . . . . . . . . . . . . . . . 18
19. Security Considerations . . . . . . . . . . . . . . . . . . . 19
20. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
21. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
21.1. Normative References . . . . . . . . . . . . . . . . . . 20
21.2. Informative References . . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22
1. Introduction
This document instructs IANA to make changes to a number of Transport
Layer Security and Datagram Transport Layer Security ((D)TLS) related
IANA registries. These changes were almost entirely motivated by the
development of TLS1.3 [I-D.ietf-tls-tls13].
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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 in this,
the introductory section, each section provides rationale for the
proposed change(s).
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] 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
{::boilerplate bcp14-tagged}
3. Add "TLS" to Registry Names
For consistency amongst TLS registries, IANA [SHALL prepend/has
prepended] "TLS" to the following registries:
* Application-Layer Protocol Negotiation (ALPN) Protocol IDs
[RFC7301],
* ExtensionType Values,
* Heartbeat Message Types [RFC6520], and
* Heartbeat Modes [RFC6520].
IANA [SHALL update/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.
4. Aligning with RFC 8126
Many of the TLS-related IANA registries were defined prior to
[RFC8126] where "IETF Consensus" was used instead of the
RFC8126-defined "IETF Review". To align with the new terminology,
IANA [SHALL update/has updated] the following registries to use "IETF
Review" in place of "IETF Consensus":
* TLS Authorization Data Formats [RFC4680]
* TLS Supplemental Data Formats (SupplementalDataType) [RFC5878]
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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].
IANA [SHALL update/has updated] the reference for these two
registries to also refer to this document.
5. Adding Recommended Column
The instructions in this document add a Recommended column to many of
the TLS registries to indicate parameters that are generally
recommended for implementations to support, parameters that are not
recommended for specific reasons, and parameters that have not been
evauated.
* Parameters that are Recommended are marked with a 'Y'.
* Parameters that are Not Recommended are maked with a 'N' and
include a reference to the document and section which describes
the limitation of the parameter.
* Parameters that are Unevaluated are unmarked with a ' '.
Adding a Recommended parameter 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. Changing the recommended status of a standards track
parameter requires standards action.
If an item is not marked as Not Recommended it does not necessarily
mean that it is flawed in all cases. A parameter that is not
recommended may have limited applicability, or may be intended only
for specific use cases as indicated in the referenced text.
If an item is marked as Unevaluated it indicates that either the item
has not been through the IETF consensus process and it may have
limited applicability, or may be intended only for specific use
cases.
[Note: the registries in the rest of the document will need to have
the recommended column updated appropriately]
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:
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* [SHALL rename/has renamed] entry 35 to "session_ticket (renamed
from "SessionTicket TLS")" [RFC5077].
* [SHALL add/has added] a reference to this document in the
Reference column for entry 35.
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
experimental and private use. Therefore, IANA [SHALL update/has
updated] the TLS ExtensionType Values registry to:
* Change 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].
* Update the "Reference" to also refer to this document.
See Section 18 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 [SHALL
update/has updated] the TLS ExtensionType Values registry to:
* Add a "Recommended" column with the contents as listed below.
This table has been generated by marking Standards Track RFCs as
"Yes" and all others as "No". Future extensions MUST define the
value of the Recommended column. In order to register an
extension with the value "Yes", a Standards Track document
[RFC8126] is REQUIRED. IESG Approval is REQUIRED for a Yes->No
transition.
+========================================+=============+
| Extension | Recommended |
+========================================+=============+
| server_name | Yes |
+----------------------------------------+-------------+
| max_fragment_length | Yes |
+----------------------------------------+-------------+
| client_certificate_url | Yes |
+----------------------------------------+-------------+
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| 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 |
+----------------------------------------+-------------+
| cached_info | Yes |
+----------------------------------------+-------------+
| session_ticket | Yes |
+----------------------------------------+-------------+
| renegotiation_info | Yes |
+----------------------------------------+-------------+
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Table 1
IANA [SHALL update/has added] the following notes:
Note: The role of the designature expert is described in [this-RFC].
The designated expert [RFC8126] ensures that the specification is
publicly available. An Internet Draft that is posted and never
published or a standard in another standards body, industry
consortium, university site, etc. suffices. 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: Extensions marked as "Yes" are those allocated via Standards
Track RFCs. Extensions marked as "No" are not.
Note: If an item is not marked as Recommended it does not
necessarily mean that it is flawed; rather, it indicates that
either the item has not been through the IETF consensus process,
has limited applicability, or is intended only for specific use
cases.
NOTE: token_binding is omitted from the above table;
[I-D.ietf-tokbind-negotiation] specifies the Recommended column
for this extension.
NOTE: The following is from [I-D.ietf-tls-tls13] and is included
here to ensure alignment between these specifications.
[I-D.ietf-tls-tls13] also uses the TLS ExtensionType Registry
originally created in [RFC4366]. IANA has updated it to reference
this document. The registry and its allocation policy is listed
below:
* IANA [SHALL update/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_certs", extensions with the values
defined in this document and the Recommended value of "Yes".
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* IANA [SHALL update/has updated] this registry to include a "TLS
1.3" column which lists the messages in which the extension may
appear. This column [SHALL be/has been] initially populated from
the table in Section 4.2 of [I-D.ietf-tls-tls13] with any
extension not listed there marked as "-" to indicate that it is
not used by TLS 1.3.
8. TLS Cipher Suite 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 Suite registry's registration
policy to Specification Required [RFC8126] while reserving a small
part of the code space for experimental and private use. Therefore,
IANA [SHALL update/has updated] the TLS Cipher Suite 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 18 for additional information about the designated expert
pool.
The cipher suite registry has grown significantly and will continue
to do so. To better guide those not intimately involved in TLS, IANA
[shall update/has updated] the TLS Cipher Suite registry as follows:
* Add a "Recommended" column to the TLS Cipher Suite registry. The
cipher suites that follow in the two tables are marked as "Yes".
All other cipher suites are marked as "No". Future cipher suites
MUST define the value of the Recommended column. In order to
register an extension with the value "Yes, a Standards Track
document [RFC8126] is REQUIRED. IESG Approval is REQUIRED for a
Yes->No transition.
The cipher suites that follow are standards track server-
authenticated (and optionally client-authenticated) cipher suites
which are currently available in TLS 1.2.
RFC EDITOR: The previous paragraph is for document reviewers and is
not meant for the registry.
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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}
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.
RFC EDITOR: The previous paragraph is for document reviewers and is
not meant for the registry.
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 | {TBD}
TLS_ECDHE_PSK_WITH_AES_256_GCM_SHA384 | {TBD}
TLS_ECDHE_PSK_WITH_AES_128_CCM_SHA256 | {TBD}
TLS_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256 | {0xCC,0xAC}
TLS_DHE_PSK_WITH_CHACHA20_POLY1305_SHA256 | {0xCC,0xAD}
Despite the following behavior being misguided, experience has shown
that some customers use the IANA registry as checklist against which
to measure an implementation's completeness and some implementers
blindly implement cipher suites. Therefore, IANA [SHALL add/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.
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IANA [SHALL add/has added] the following note to ensure that those
that focus on IANA registries are aware that TLS 1.3
[I-D.ietf-tls-tls13] 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 cannot be used for TLS
1.2. Similarly, TLS 1.2 and lower cipher suite values cannot be
used with TLS 1.3.
IANA [SHALL add/has added] the following notes to document the rules
for populating the Recommended column:
Note: Cipher suites marked as "Yes" are those allocated via
Standards Track RFCs. Cipher suites marked as "No" are not;
cipher suites marked "No" range from "good" to "bad" from a
cryptographic standpoint.
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.
Note: If an item is not marked as Recommended it does not
necessarily mean that it is flawed; rather, it indicates that
either the item has not been through the IETF consensus process,
has limited applicability, or is intended only for specific use
cases.
IANA [SHALL add/has added] the following notes for additional
information:
Note: The role of the designature expert is described in [this-RFC].
The designated expert [RFC8126] ensures that the specification is
publicly available. An Internet Draft that is posted and never
published or a standard in another standards body, industry
consortium, university site, etc. suffices. 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.
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IANA [SHALL update/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 [SHALL add/has added] 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;
[I-D.ietf-tls-rfc4492bis] elevates secp256r1 and secp384r1 to
Standards Track. Not all groups from [I-D.ietf-tls-rfc4492bis],
which is standards track, are marked as "Yes"; these groups apply to
TLS 1.3 [I-D.ietf-tls-tls13] and previous versions of TLS. Future
supported groups MUST define the value of this column. In order to
register an extension with the value "Yes", a Standards Track
document [RFC8126] is REQUIRED. IESG Approval is REQUIRED for a
Yes->No transition.
IANA [SHALL add/has added] the following note:
Note: Supported Groups marked as "Yes" are those allocated via
Standards Track RFCs. Supported Groups marked as "No" are not;
supported groups marked "No" range from "good" to "bad" from a
cryptographic standpoint.
Note: If an item is not marked as Recommended it does not
necessarily mean that it is flawed; rather, it indicates that
either the item has not been through the IETF consensus process,
has limited applicability, or is intended only for specific use
cases.
Note: The role of the designature expert is described in [this-RFC].
The designated expert [RFC8126] ensures that the specification is
publicly available. An Internet Draft that is posted and never
published or a standard in another standards body, industry
consortium, university site, etc. suffices. 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 checklist against which
to measure an implementation's completeness and some implementers
blindly implement groups supported. Therefore, IANA [SHALL add/has
added] the following warning to the registry:
WARNING: Cryptographic algorithms and parameters will be broken or
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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 [SHALL update/has updated] the reference for this registry to
also refer to this document.
The value 0 (0x0000) is to be 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 registration policy to
Specification Required [RFC8126] while reserving a small part of the
code space for experimental and private use. Therefore, IANA [SHALL
update/has updated] the TLS Cipher Suite registry's policy as
follows:
Values in the range 0-223 are assigned via Specification Required
[RFC8126]. Values 224-255 are reserved for Private Use.
See Section 18 for additional information about the designated expert
pool.
IANA [SHALL add/has added] the following notes:
Note: The role of the designature expert is described in [this-RFC].
The designated expert [RFC8126] ensures that the specification is
publicly available. An Internet Draft that is posted and never
published or a standard in another standards body, industry
consortium, university site, etc. suffices. 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.
Note: ClientCertificateType Identifiers marked as "Yes" are those
allocated via Standards Track RFCs. ClientCertificateTypes marked
as "No" are not.
Note: If an item is not marked as Recommended it does not
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necessarily mean that it is flawed; rather, it indicates that
either the item has not been through the IETF consensus process,
has limited applicability, or is intended only for specific use
cases.
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:
* [SHALL rename/has renamed] entry 4 in the TLS HandshakeType
registry to "new_session_ticket (renamed from NewSessionTicket)"
[RFC5077].
* [SHALL add/has added] a reference to this document in the
Reference column for entry 4 in the TLS HandshakeType registry.
12. TLS Exporter Label Registry
To aid those reviewers who start with the IANA registry, IANA [SHALL
add/has added]:
* 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 differently.
* 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. In order to register an
extension with the value "Yes", a Standards Track document
[RFC8126] is REQUIRED. IESG Approval is REQUIRED for a Yes->No
transition.
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Exporter Value | Recommended |
--------------------------------|-------------|
client finished | Yes |
server finished | Yes |
master secret | Yes |
key expansion | Yes |
client EAP encryption | Yes |
ttls keying material | Yes |
ttls challenge | Yes |
EXTRACTOR-dtls_srtp | Yes |
EXPORTER_DTLS_OVER_SCTP | Yes |
EXPORTER: teap session key seed | Yes |
To provide additional information for the designated experts, IANA
[SHALL add/has added] the following note:
Note: The role of the designature expert is described in [this-RFC].
The designated expert [RFC8126] ensures that the specification is
publicly available. An Internet Draft that is posted and never
published or a standard in another standards body, industry
consortium, university site, etc. suffices. The expert may
provide more in depth reviews, but their approval should not be
taken as an endorsement of the exporter. 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: Exporters Labels marked as "Yes" are those allocated via
Standards Track RFCs. Exporter Labels marked as "No" are not.
Note: If an item is not marked as Recommended it does not
necessarily mean that it is flawed; rather, it indicates that
either the item has not been through the IETF consensus process,
has limited applicability, or is intended only for specific use
cases.
IANA [SHALL update/has updated] the reference for this registry to
also refer to this document.
13. Add Missing Item to TLS Alert Registry
IANA [SHALL add/has added] the following entry to the TLS Alert
Registry; the entry was omitted from the IANA instructions in
[RFC7301]:
120 no_application_protocol Y [RFC7301][this-RFC]
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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
experimental and private use. Therefore, IANA [SHALL change/has
changed] the TLS Certificate Types regisry to:
* Change the registry policy to:
Values with the first byte in the range 0-223 (decimal) are
assigned via Specification Required [RFC8126]. Values with the
first byte 224-255 (decimal) are reserved for Private Use
[RFC8126].
* Add a "Recommended" column to the registry. X.509 and Raw Public
Key are "Yes". All others are "No". In order to register an
extension with the value "Yes", a Standards Track document
[RFC8126] is REQUIRED. Future Certificate Types MUST define the
value of this column. A Standards Track document [RFC8126] is
REQUIRED to register an entry with the value "Yes". IESG Approval
is REQUIRED for a Yes->No transition.
See Section 18 for additional information about the designated expert
pool.
IANA [SHALL add/has added] the following note:
Note: The role of the designature expert is described in [this-RFC].
The designated expert [RFC8126] ensures that the specification is
publicly available. An Internet Draft that is posted and never
published or a standard in another standards body, industry
consortium, university site, etc. suffices. The expert may
provide more in depth reviews, but their approval should not be
taken as an endorsement of the certificate type.
Note: Certificate Types marked as "Yes" are those allocated via
Standards Track RFCs. Certificate Types marked as "No" are not.
Note: If an item is not marked as Recommended it does not
necessarily mean that it is flawed; rather, it indicates that
either the item has not been through the IETF consensus process,
has limited applicability, or is intended only for specific use
cases.
IANA [SHALL update/has updated] the reference for this registry to
also refer this document.
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15. Orphaned Extensions
To make it clear that (D)TLS 1.3 has orphaned certain extensions
(i.e., some extensions are only applicable to version of (D)TLS prior
to 1.3), IANA [SHALL add/has added] the following note to the TLS
ExtensionType Values registry:
Note: The following extensions are only applicable to (D)TLS
protocol versions prior to 1.3: trusted_ca_keys, truncated_hmac,
user_mapping, cert_type, ec_point_formats, srp, status_request_v2,
encrypt_then_mac, extended_master_secret, session_ticket, and
renegotiation_info. These extensions are not applicable to (D)TLS
1.3.
16. 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:
* [SHALL add/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.
* [SHALL add/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.
* [SHALL update/has updated] the "Reference" field in the TLS
Compression Method Identifiers, TLS HashAlgorithm and TLS
SignatureAlgorithm registries to also refer to this document.
* [SHALL update/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".
Despite the fact that the 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 [SHALL add/
has added] the following warning to the HashAlgorithm and
SignatureAlgorithm:
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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.
17. Experimental Codepoints
Many of the Transport Layer Security (TLS) IANA registries currently
use the Specification Required registration policy for unassigned
values, along with a small block reserved for Private Use. As
specified in [RFC8126], assignments made in the Private Use space are
not useful for broad interoperability experiments. Therefore,
experimental code points which require large-scale interopable
experiments must use values from the unassigned range. Currently,
nothing prevents applications from using unassigned codepoints
without an IANA assignment. This means that applications which
request an assignment according to this procedure via a specification
may inadvertently choose a codepoint value that some other
application is squatting on. In turn, this negatively may impact
experiments.
To promote visibility of unassigned codepoints and lower the bar for
large-scale experiments, this draft outlines a different registration
policy for TLS registries. In particular, it allocates a number of
contiguous codepoints for experimental purposes and delegates
management of this space to the Working Group contributors.
This section describes experimental codepoint blocks for IANA
registries related to TLS, including: Extensions Section 17.1 and
Supported Groups Section 17.2. For each of these registries, this
document allocates a set of experimental codepoint blocks from the
unassigned space in the registry. Each codepoint in this range is
then managed by the Working Group contributors via a publicly
accessible and transparent page with changes tracked by version
control on GitHub (https://github.com/) or another similar service.
The details of each experimental codepoint are tracked in a table,
which lists information about the request along with expiration
information. Table details are documented in the following sections.
The registration policy of additional experimental codepoint blocks
for these registries is Specification Required [RFC8126].
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Applications request experimental codepoints in these blocks by
requesting changes to the corresponding table. Each request
indicates a value, name, and a corresponding reference. Requests
without these contents will be rejected. The expiry date column will
be initialized to a date 1 year from the day the entry was created.
When the expiry date is reached the entry is evaluated to determine
if it can be returned back to the pool. If the codepoint is still in
use then it may be renewed for another year period.
Experimental codepoint values will be distributed on a first-come-
first-serve basis. All experimental assignments will be temporary.
[OPEN ISSUE: should experimental code blocks be added for all other
registries?]
17.1. Extensions
The Extensions registry page will host a table with the four columns:
(1) Codepoint, (2) Extension Name, (3) Reference, and (4) Expiry
Date.
IANA is requested to create the following entries in the existing
Transport Layer Security (TLS) Extensions registry:
* experimental_block_1(64251-65279), with the "TLS 1.3" column
values set to "N/A" and "Recommended" column set to "No".
17.2. Supported Groups
The Supported Groups registry page will host a table with the four
columns: (1) Codepoint, (2) Supported Group Name, (3) Reference, and
(4) Expiry Date.
IANA is requested to create the following entries in the existing
Transport Layer Security (TLS) Supported Groups registry:
* experimental_block_1(64251-65023), with the "DTLS-OK" column
values set to "N/A" and "Recommended" column set to "No".
18. 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.
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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
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.
19. 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.
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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.
This document introduces a new procedure for requesting and managing
experimental TLS extension values. Codepoint collisions, which may
produce interoperability or security issues, may still occur in
practice for applications which do not use the existing procedures or
those defined herein. The new procedure aims to mitigate this risk
going forward with an easy-to-use range of experimental codepoints.
Any extension using a code point in this space is considered a work
in progress. There may be security or interoperability problems with
the extension. The extension specification may change without
notice.
20. IANA Considerations
This document is entirely about changes to TLS-related IANA
registries. This revision of the document only has IANA actions in
the following sections:
{#experiment} Experimental Codepoints
21. References
21.1. Normative References
[I-D.ietf-tls-tls13]
Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", Work in Progress, Internet-Draft, draft-
ietf-tls-tls13-28, 20 March 2018, <http://www.ietf.org/
internet-drafts/draft-ietf-tls-tls13-28.txt>.
[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>.
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[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>.
[RFC6655] McGrew, D. and D. Bailey, "AES-CCM Cipher Suites for
Transport Layer Security (TLS)", RFC 6655,
DOI 10.17487/RFC6655, July 2012,
<https://www.rfc-editor.org/info/rfc6655>.
[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>.
21.2. 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", Work in
Progress, Internet-Draft, draft-ietf-tls-rfc4492bis-17, 5
May 2017, <https://www.ietf.org/archive/id/draft-ietf-tls-
rfc4492bis-17.txt>.
[I-D.ietf-tokbind-negotiation]
Popov, A., Nyström, M., Balfanz, D., and A. Langley,
"Transport Layer Security (TLS) Extension for Token
Binding Protocol Negotiation", Work in Progress, Internet-
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Draft, draft-ietf-tokbind-negotiation-14, 23 May 2018,
<https://www.ietf.org/archive/id/draft-ietf-tokbind-
negotiation-14.txt>.
[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>.
Authors' Addresses
Joe Salowey
Salesforce
Email: joe@salowey.net
Sean Turner
sn3rd
Email: sean@sn3rd.com
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