JWTClaimConstraints profile of ACME Authority Token
draft-wendt-acme-authority-token-jwtclaimcon-00
This document is an Internet-Draft (I-D).
Anyone may submit an I-D to the IETF.
This I-D is not endorsed by the IETF and has no formal standing in the
IETF standards process.
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 | Chris Wendt , David Hancock | ||
| Last updated | 2025-03-03 | ||
| Replaced by | draft-ietf-acme-authority-token-jwtclaimcon | ||
| 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-wendt-acme-authority-token-jwtclaimcon-00
Network Working Group C. Wendt
Internet-Draft D. Hancock
Intended status: Standards Track Somos Inc.
Expires: 4 September 2025 3 March 2025
JWTClaimConstraints profile of ACME Authority Token
draft-wendt-acme-authority-token-jwtclaimcon-00
Abstract
This document defines an authority token profile for handling the
validation of JWTClaimConstraints and Enhanced JWTClaimConstraints.
This profile follows the model established in Authority Token for the
validation of TNAuthList but is specifically tailored for the
JWTClaimConstraints certificate extensions. The profile enables
validation and challenge processes necessary to support certificates
containing both TNAuthList and JWTClaimConstraints, particularly in
the context of Secure Telephone Identity (STI).
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 4 September 2025.
Copyright Notice
Copyright (c) 2025 IETF Trust and the persons identified as the
document authors. All rights reserved.
Wendt & Hancock Expires 4 September 2025 [Page 1]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
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 Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. ACME new-order identifiers for JWTClaimConstraints . . . . . 3
4. JWTClaimConstraints Authorization . . . . . . . . . . . . . . 5
5. JWTClaimConstraints Authority Token . . . . . . . . . . . . . 7
5.1. "iss" claim . . . . . . . . . . . . . . . . . . . . . . . 7
5.2. "exp" claim . . . . . . . . . . . . . . . . . . . . . . . 8
5.3. "jti" claim . . . . . . . . . . . . . . . . . . . . . . . 8
5.4. "atc" claim . . . . . . . . . . . . . . . . . . . . . . . 8
5.5. Acquiring the token from the Token Authority . . . . . . 9
5.6. Token Authority Responsibilities . . . . . . . . . . . . 10
5.7. Scope of the JWTClaimConstraints . . . . . . . . . . . . 11
6. Validating the JWTClaimConstraints Authority Token . . . . . 11
7. Using ACME-issued Certificates with JSON Web Signature . . . 12
8. Usage Considerations . . . . . . . . . . . . . . . . . . . . 13
8.1. Large number of Non-contiguous TNAuthList values . . . . 13
9. Security Considerations . . . . . . . . . . . . . . . . . . . 14
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
12.1. Normative References . . . . . . . . . . . . . . . . . . 14
12.2. Informative References . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction
The validation of JWTClaimConstraints as part of an STI certificate
defined in [RFC8226] is critical for ensuring the integrity and scope
of claims used in PASSporTs. This document specifies an authority
token profile for validating JWTClaimConstraints, modeled after the
authority token framework established in [RFC9447] and the TNAuthList
validation defined in [RFC9448]. This profile facilitates proper
delegation and authorization for entities requesting certificates
under ACME [RFC8555] and similar frameworks.
Wendt & Hancock Expires 4 September 2025 [Page 2]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
This Authority Token profile specifically addresses the inclusions of
the STI certificate extensions JWTClaimConstraints, as defined in
[RFC8226], and Enhanced JWTClaimConstraints, as defined in [RFC9118].
The STI certificate credentials are used to sign PASSporTs [RFC8225],
which can be carried in using protocols such as SIP [RFC8224]. This
document defines the use of the JWTClaimConstraints Authority Token
in the ACME challenge to proof an authoritative or trusted use of the
contents of the JWTClaimsConstraint based on the issuer of the token.
The Certification Authority (CA) issuing the STI Certificate can be
informed of the proper use and contents of the JWTClaimConstraints
based on the STI eco-system policies, best practices, or
authoritative information which is out of scope of this document and
will be defined by the STI eco-system.
This document also discusses the ability for a telephone authority to
authorize the creation of CA types of certificates for delegation as
defined in [RFC9060].
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. ACME new-order identifiers for JWTClaimConstraints
In [RFC8555], Section 7 defines the procedure that an ACME client
uses to order a new certificate from a Certification Authority (CA).
The new-order request contains an identifier field that specifies the
identifier objects the order corresponds to. This draft defines a
new type of identifier object called JWTClaimConstraints. A
JWTClaimConstraints identifier contains the Token Claim Constraints
information to be populated in the JWTClaimConstraints or Enhanced
JWTClaimConstraints of the new certificate. For the
JWTClaimConstraints identifier, the new-order request includes a type
set to the string "JWTClaimConstraints". The value of the
JWTClaimConstraints identifier MUST be set to the details of the
JWTClaimConstraints requested.
The format of the string that represents the JWTClaimConstraints MUST
be constructed using base64url encoding, as per [RFC8555] base64url
encoding described in Section 5 of [RFC4648] according to the profile
specified in JSON Web Signature in Section 2 of [RFC7515]. The
base64url encoding MUST NOT include any padding characters and the
JWTClaimConstraints ASN.1 object MUST encoded using DER encoding
rules.
Wendt & Hancock Expires 4 September 2025 [Page 3]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
An example of an ACME order object “identifiers” field containing a
JWTClaimConstraints certificate would look as follows,
"identifiers": [{"type":"JWTClaimConstraints",
"value":"F83n2a...avn27DN3"}]
where the "value" object string represents the arbitrary length
base64url encoded string.
A full new-order request would look as follows,
POST /acme/new-order HTTP/1.1
Host: example.com
Content-Type: application/jose+json
{
"protected": base64url({
"alg": "ES256",
"kid": "https://example.com/acme/acct/evOfKhNU60wg",
"nonce": "5XJ1L3lEkMG7tR6pA00clA",
"url": "https://example.com/acme/new-order"
}),
"payload": base64url({
"identifiers": [{"type":"JWTClaimConstraints",
"value":"F83n...n27DN3"}],
"notBefore": "2025-01-01T00:00:00Z",
"notAfter": "2025-01-08T00:00:00Z"
}),
"signature": "H6ZXtGjTZyUnPeKn...wEA4TklBdh3e454g"
}
On receiving a valid new-order request, the ACME server creates an
authorization object, [RFC8555] Section 7.1.4, containing the
challenge that the ACME client must satisfy to demonstrate authority
for the identifiers specified by the new order (in this case, the
JWTClaimConstraints identifier). The CA adds the authorization
object URL to the "authorizations" field of the order object, and
returns the order object to the ACME client in the body of a 201
(Created) response.
Wendt & Hancock Expires 4 September 2025 [Page 4]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
HTTP/1.1 201 Created
Content-Type: application/json
Replay-Nonce: MYAuvOpaoIiywTezizk5vw
Location: https://example.com/acme/order/1234
{
"status": "pending",
"expires": "2025-01-08T00:00:00Z",
"notBefore": "2025-01-01T00:00:00Z",
"notAfter": "2025-01-08T00:00:00Z",
"identifiers":[{"type":"JWTClaimConstraints",
"value":"F83n2a...avn27DN3"}],
"authorizations": [
"https://example.com/acme/authz/1234"
],
"finalize": "https://example.com/acme/order/1234/finalize"
}
4. JWTClaimConstraints Authorization
On receiving the new-order response, the ACME client queries the
referenced authorization object to obtain the challenges for the
identifier contained in the new-order request as shown in the
following example request and response.
POST /acme/authz/1234 HTTP/1.1
Host: example.com
Content-Type: application/jose+json
{
"protected": base64url({
"alg": "ES256",
"kid": " https://example.com/acme/acct/evOfKhNU60wg",
"nonce": "uQpSjlRb4vQVCjVYAyyUWg",
"url": "https://example.com/acme/authz/1234"
}),
"payload": "",
"signature": "nuSDISbWG8mMgE7H...QyVUL68yzf3Zawps"
}
Wendt & Hancock Expires 4 September 2025 [Page 5]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
HTTP/1.1 200 OK
Content-Type: application/json
Link: <https://example.com/acme/some-directory>;rel="index"
{
"status": "pending",
"expires": "2025-01-08T00:00:00Z",
"identifier": {
"type:"JWTClaimConstraints",
"value":"F83n2a...avn27DN3"
},
"challenges": [
{
"type": "tkauth-01",
"tkauth-type": "atc",
"token-authority": "https://authority.example.org",
"url": "https://example.com/acme/chall/prV_B7yEyA4",
"token": "IlirfxKKXAsHtmzK29Pj8A"
}
]
}
When processing a certificate order containing an identifier of type
"JWTClaimConstraints", a CA uses the Authority Token challenge type
of "tkauth-01" with a "tkauth-type" of "atc" in [RFC9447] to verify
that the requesting ACME client has authenticated and authorized
control over the requested resources represented by the
"JWTClaimConstraints" value.
The challenge "token-authority" parameter is optional and is only
used in cases where the VoIP telephone network requires the CA to
identify the Token Authority. If a "token-authority" parameter is
present, then the ACME client MAY use the "token-authority" value to
identify the URL representing the Token Authority that will provide
the JWTClaimConstraints Authority Token response to the challenge.
If the "token-authority" parameter is not present, then the ACME
client MUST identify the Token Authority based on locally configured
information or local policies.
The ACME client responds to the challenge by posting the
JWTClaimConstraints Authority Token to the challenge URL identified
in the returned ACME authorization object, an example of which
follows.
Wendt & Hancock Expires 4 September 2025 [Page 6]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
POST /acme/chall/prV_B7yEyA4 HTTP/1.1
Host: boulder.example.com
Content-Type: application/jose+json
{
"protected": base64url({
"alg": "ES256",
"kid": "https://example.com/acme/acct/evOfKhNU60wg",
"nonce": "Q_s3MWoqT05TrdkM2MTDcw",
"url": "https://boulder.example.com/acme/authz/asdf/0"
}),
"payload": base64url({
"tkauth": "DGyRejmCefe7v4N...vb29HhjjLPSggwiE"
}),
"signature": "9cbg5JO1Gf5YLjjz...SpkUfcdPai9uVYYQ"
}
The "tkauth" field is defined as a new field in the challenge object
specific to the tkauth-01 challenge type that should contain the
JWTClaimConstraints Authority Token defined in the next section.
5. JWTClaimConstraints Authority Token
The Telephone Number Authority List Authority Token
(JWTClaimConstraints Authority Token) is a profile instance of the
ACME Authority Token defined in [RFC9447].
The JWTClaimConstraints Authority Token Protected header MUST comply
with the Authority Token Protected header as defined in [RFC9447].
The JWTClaimConstraints Authority Token Payload MUST include the
mandatory claims "exp", "jti", and "atc", and MAY include the
optional claims defined for the Authority Token detailed in the next
subsections.
5.1. "iss" claim
The "iss" claim is an optional claim defined in [RFC7519]
Section 4.1.1. It can be used as a URL identifying the Token
Authority that issued the JWTClaimConstraints Authority Token beyond
the "x5u" or other Header claims that identify the location of the
certificate or certificate chain of the Token Authority used to
validate the JWTClaimConstraints Authority Token.
Wendt & Hancock Expires 4 September 2025 [Page 7]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
5.2. "exp" claim
The "exp" claim, defined in [RFC7519] Section 4.1.4, MUST be included
and contains the DateTime value of the ending date and time that the
JWTClaimConstraints Authority Token expires.
5.3. "jti" claim
The "jti" claim, defined in [RFC7519] Section 4.1.7, MUST be included
and contains a unique identifier for this JWTClaimConstraints
Authority Token transaction.
5.4. "atc" claim
The "atc" claim MUST be included and is defined in [RFC9447]. It
contains a JSON object with the following elements:
* a "tktype" key with a string value equal to "JWTClaimConstraints"
to represent a JWTClaimConstraints profile of the authority token
[RFC9447] defined by this document. "tktype" is a required key and
MUST be included.
* a "tkvalue" key with a string value equal to the base64url
encoding of the TN Authorization List certificate extension ASN.1
object using DER encoding rules. "tkvalue" is a required key and
MUST be included.
* a "ca" key with a boolean value set to either true when the
requested certificate is allowed to be a CA cert for delegation
uses or false when the requested certificate is not intended to be
a CA cert, only an end-entity certificate. "ca" is an optional
key, if not included the "ca" value is considered false by
default.
* a "fingerprint" key is constructed as defined in [RFC8555]
Section 8.1 corresponding to the computation of the "Thumbprint"
step using the ACME account key credentials. "fingerprint" is a
required key and MUST be included.
An example of the JWTClaimConstraints Authority Token is as follows:
Wendt & Hancock Expires 4 September 2025 [Page 8]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
{
"protected": base64url({
"typ":"JWT",
"alg":"ES256",
"x5u":"https://authority.example.org/cert"
}),
"payload": base64url({
"iss":"https://authority.example.org",
"exp":1640995200,
"jti":"id6098364921",
"atc":{"tktype":"JWTClaimConstraints",
"tkvalue":"F83n2a...avn27DN3",
"ca":false,
"fingerprint":"SHA256 56:3E:CF:AE:83:CA:4D:15:B0:29:FF:1B:71:
D3:BA:B9:19:81:F8:50:9B:DF:4A:D4:39:72:E2:B1:F0:B9:38:E3"}
}),
"signature": "9cbg5JO1Gf5YLjjz...SpkUfcdPai9uVYYQ"
}
5.5. Acquiring the token from the Token Authority
Following [RFC9447] Section 5, the authority token should be acquired
using a RESTful HTTP POST transaction as follows:
POST /at/account/:id/token HTTP/1.1
Host: authority.example.org
Content-Type: application/json
The request will pass the account id as a string in the request
parameter "id". This string will be managed as an identifier
specific to the Token Authority's relationship with the entity that
is creating and signing a PASSporT [RFC8225] and making the
Certificate Signing Request via ACME. There is assumed to also be a
corresponding authentication procedure that can be verified for the
success of this transaction. For example, an HTTP authorization
header containing a valid authorization credentials as defined in
[RFC7231] Section 14.8.
The body of the POST request MUST contain a JSON object with key
value pairs corresponding to values that are requested as the content
of the claims in the issued token. As an example, the body SHOULD
contain a JSON object as follows:
Wendt & Hancock Expires 4 September 2025 [Page 9]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
{
"tktype":"JWTClaimConstraints",
"tkvalue":"F83n2a...avn27DN3",
"ca":false,
"fingerprint":"SHA256 56:3E:CF:AE:83:CA:4D:15:B0:29:FF:1B:71:D3
:BA:B9:19:81:F8:50:9B:DF:4A:D4:39:72:E2:B1:F0:B9:38:E3"
}
The response to the POST request if successful returns a 200 OK with
a JSON body that contains, at a minimum, the JWTClaimConstraints
Authority Token as a JSON object with a key of "token" and the
base64url encoded string representing the atc token. JSON is easily
extensible, so users of this specification may want to pass other
pieces of information relevant to a specific application.
An example successful response would be as follows:
HTTP/1.1 200 OK
Content-Type: application/json
{"token": "DGyRejmCefe7v4N...vb29HhjjLPSggwiE"}
If the request is not successful, the response should indicate the
error condition. Specifically, for the case that the authorization
credentials are invalid or if the Account ID provided does not exist,
the response code MUST be 403 - Forbidden. Other 4xx and 5xx
responses MUST follow standard [RFC7231] HTTP error condition
conventions.
5.6. Token Authority Responsibilities
When creating the JWTClaimConstraints Authority Token, the Token
Authority MUST validate that the information contained in the ASN.1
JWTClaimConstraints accurately represents the corresponding
JWTClaimConstraint resources the requesting party is authorized to
represent based on their pre-established and verified secure
relationship between the Token Authority and the requesting party.
Note that the fingerprint in the token request is not meant to be
verified by the Token Authority, but rather is meant to be signed as
part of the token so that the party that requests the token can, as
part of the challenge response, allow the ACME server to validate the
token requested and used came from the same party that controls the
ACME client.
Wendt & Hancock Expires 4 September 2025 [Page 10]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
5.7. Scope of the JWTClaimConstraints
Because this specification specifically involves the
JWTClaimConstraints and Enhanced JWTClaimConstraints defined in
[RFC8226] and [RFC9118] which involves the required or disallowed
different claim types or claim values, the client may also request an
Authority Token with some subset of its own authority as the
JWTClaimConstraints provided in the "tkvalue" element in the "atc"
JSON object. JWTClaimConstraints can be constructed to define a
limited scope of claims and claim values the client has authority
over.
As recommended in [RFC9447] security considerations, an Authority
Token can either have a scope that attests all of the resources which
a client is eligible to receive certificates for, or potentially a
more limited scope that is intended to capture only those resources
for which a client will receive a certificate from a particular
certification authority. Any certification authority that sees an
Authority Token can learn information about the resources a client
can claim. In cases where this incurs a privacy risk, Authority
Token scopes should be limited to only the resources that will be
attested by the requested ACME certificate.
6. Validating the JWTClaimConstraints Authority Token
Upon receiving a response to the challenge, the ACME server MUST
perform the following steps to determine the validity of the
response.
* Verify that the value of the "atc" claim is a well-formed JSON
object containing the mandatory key values.
* If there is an "x5u" parameter verify the "x5u" parameter is a
HTTPS URL with a reference to a certificate representing the
trusted issuer of authority tokens for the eco-system.
* If there is an "x5c" parameter verify the certificate array
contains a certificate representing the trusted issuer of
authority tokens for the eco-system.
* Verify the JWTClaimConstraints Authority Token signature using the
public key of the certificate referenced by the token's "x5u" or
"x5c" parameter.
* Verify that "atc" claim contains a "tktype" identifier with the
value "JWTClaimConstraints".
Wendt & Hancock Expires 4 September 2025 [Page 11]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
* Verify that the "atc" claim "tkvalue" identifier contains the
equivalent base64url encoded JWTClaimConstraints certificate
extension string value as the Identifier specified in the original
challenge.
* Verify that the remaining claims are valid (e.g., verify that
token has not expired)
* Verify that the "atc" claim "fingerprint" is valid and matches the
account key of the client making the request
* Verify that the "atc" claim "ca" identifier boolean corresponds to
the CA boolean in the Basic Constraints extension in the CSR for
either CA certificate or end-entity certificate
If all steps in the token validation process pass, then the ACME
server MUST set the challenge object "status" to "valid". If any
step of the validation process fails, the "status" in the challenge
object MUST be set to "invalid".
7. Using ACME-issued Certificates with JSON Web Signature
JSON Web Signature (JWS, [RFC7515]) objects can include an "x5u"
header parameter to refer to a certificate that is used to validate
the JWS signature. For example, the STIR PASSporT framework
[RFC8225] uses "x5u" to indicate the STIR certificate used to
validate the PASSporT JWS object. The URLs used in "x5u" are
expected to provide the required certificate in response to a GET
request, not a POST-as-GET as required for the "certificate" URL in
the ACME order object. Thus the current mechanism generally requires
the ACME client to download the certificate and host it on a public
URL to make it accessible to relying parties. This section defines
an optional mechanism for the Certificate Authority (CA) to host the
certificate directly and provide a URL that the ACME client owner can
directly reference in the "x5u" of their signed PASSporTs.
As described in Section 7.4 of [RFC8555] when the certificate is
ready for making a finalize request, the server will return a 200
(OK) with the updated order object. In this response, an ACME Server
can add a newly defined field called "x5u" that can pass this URL to
the ACME client for usage in generated PASSporTs as a publicly
available URL for PASSporT validation.
x5u (optional, string): A URL that can be used to reference the
certificate in the "x5u" parameter of a JWS object [RFC7515]
Wendt & Hancock Expires 4 September 2025 [Page 12]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
The publishing of the certificates at the new "x5u" URL should follow
the GET request requirement as mentioned above and should be
consistent with the timely publication according to the durations of
the certificate lifecycle.
The following is an example of the use of "x5u" in the response when
the certificate status is "valid".
HTTP/1.1 200 OK
Content-Type: application/json
Replay-Nonce: CGf81JWBsq8QyIgPCi9Q9X
Link: <https://example.com/acme/directory>;rel="index"
Location: https://example.com/acme/order/TOlocE8rfgo
{
"status": "valid",
"expires": "2016-01-20T14:09:07.99Z",
"notBefore": "2016-01-01T00:00:00Z",
"notAfter": "2016-01-08T00:00:00Z",
"identifiers": [
"type":"TNAuthList",
"value":"F83n2a...avn27DN3"
],
"authorizations": ["https://sti-ca.com/acme/authz/1234"],
"finalize": "https://example.com/acme/order/TOlocE8rfgo/finalize",
"certificate": "https://example.com/acme/cert/mAt3xBGaobw",
"x5u": "https://example.com/cert-repo/giJI53km23.pem"
}
8. Usage Considerations
8.1. Large number of Non-contiguous TNAuthList values
There are many scenarios and reasons to have various combinations of
SPCs, TNs, and TN Ranges. [RFC8226] has provided a somewhat
unbounded set of combinations. It's possible that a complex non-
contiguous set of telephone numbers are being managed by a CSP. Best
practice may be simply to split a set of non-contiguous numbers under
management into multiple STI certificates to represent the various
contiguous parts of the greater non-contiguous set of TNs,
particularly if length of the set of values in identifier object
grows to be too large.
Wendt & Hancock Expires 4 September 2025 [Page 13]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
9. Security Considerations
The token represented by this document has the credentials to
represent the scope of a telephone number, a block of telephone
numbers, or an entire set of telephone numbers represented by an SPC.
The creation, transport, and any storage of this token MUST follow
the strictest of security best practices beyond the recommendations
of the use of encrypted transport protocols in this document to
protect it from getting in the hands of bad actors with illegitimate
intent to impersonate telephone numbers.
This document inherits the security properties of [RFC9447].
Implementations should follow the best practices identified in
[RFC8725].
This document only specifies SHA256 for the fingerprint hash.
However, the syntax of the fingerprint object would permit other
algorithms if, due to concerns about algorithmic agility, a more
robust algorithm were required at a future time. Future
specifications can define new algorithms for the fingerprint object
as needed.
10. IANA Considerations
This document requests the addition of a new identifier object type
to the "ACME Identifier Types" registry defined in Section 9.7.7 of
[RFC8555].
+---------------------+-----------+
| Label | Reference |
+---------------------+-----------+
| JWTClaimConstraints | RFCThis |
+---------------------+-----------+
11. Acknowledgements
We would like to thank ACME and STIR working groups for valuable
contributions to the authority token framework used in this document.
12. References
12.1. 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/rfc/rfc2119>.
Wendt & Hancock Expires 4 September 2025 [Page 14]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
<https://www.rfc-editor.org/rfc/rfc4648>.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014,
<https://www.rfc-editor.org/rfc/rfc7231>.
[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, <https://www.rfc-editor.org/rfc/rfc7515>.
[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
<https://www.rfc-editor.org/rfc/rfc7519>.
[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/rfc/rfc8174>.
[RFC8226] Peterson, J. and S. Turner, "Secure Telephone Identity
Credentials: Certificates", RFC 8226,
DOI 10.17487/RFC8226, February 2018,
<https://www.rfc-editor.org/rfc/rfc8226>.
[RFC8555] Barnes, R., Hoffman-Andrews, J., McCarney, D., and J.
Kasten, "Automatic Certificate Management Environment
(ACME)", RFC 8555, DOI 10.17487/RFC8555, March 2019,
<https://www.rfc-editor.org/rfc/rfc8555>.
[RFC8725] Sheffer, Y., Hardt, D., and M. Jones, "JSON Web Token Best
Current Practices", BCP 225, RFC 8725,
DOI 10.17487/RFC8725, February 2020,
<https://www.rfc-editor.org/rfc/rfc8725>.
[RFC9060] Peterson, J., "Secure Telephone Identity Revisited (STIR)
Certificate Delegation", RFC 9060, DOI 10.17487/RFC9060,
September 2021, <https://www.rfc-editor.org/rfc/rfc9060>.
[RFC9118] Housley, R., "Enhanced JSON Web Token (JWT) Claim
Constraints for Secure Telephone Identity Revisited (STIR)
Certificates", RFC 9118, DOI 10.17487/RFC9118, August
2021, <https://www.rfc-editor.org/rfc/rfc9118>.
Wendt & Hancock Expires 4 September 2025 [Page 15]
Internet-Draft ACME JWTClaimConstraints Auth Token March 2025
[RFC9447] Peterson, J., Barnes, M., Hancock, D., and C. Wendt,
"Automated Certificate Management Environment (ACME)
Challenges Using an Authority Token", RFC 9447,
DOI 10.17487/RFC9447, September 2023,
<https://www.rfc-editor.org/rfc/rfc9447>.
[RFC9448] Wendt, C., Hancock, D., Barnes, M., and J. Peterson,
"TNAuthList Profile of Automated Certificate Management
Environment (ACME) Authority Token", RFC 9448,
DOI 10.17487/RFC9448, September 2023,
<https://www.rfc-editor.org/rfc/rfc9448>.
12.2. Informative References
[RFC8224] Peterson, J., Jennings, C., Rescorla, E., and C. Wendt,
"Authenticated Identity Management in the Session
Initiation Protocol (SIP)", RFC 8224,
DOI 10.17487/RFC8224, February 2018,
<https://www.rfc-editor.org/rfc/rfc8224>.
[RFC8225] Wendt, C. and J. Peterson, "PASSporT: Personal Assertion
Token", RFC 8225, DOI 10.17487/RFC8225, February 2018,
<https://www.rfc-editor.org/rfc/rfc8225>.
Authors' Addresses
Chris Wendt
Somos Inc.
United States of America
Email: chris@appliedbits.com
David Hancock
Somos Inc.
United States of America
Email: davidhancock.ietf@gmail.com
Wendt & Hancock Expires 4 September 2025 [Page 16]