Internet DRAFT - draft-terbu-sd-jwt-vc
draft-terbu-sd-jwt-vc
TODO Working Group O. Terbu
Internet-Draft Spruce Systems, Inc.
Intended status: Standards Track D. Fett
Expires: 27 November 2023 Authlete Inc.
26 May 2023
SD-JWT-based Verifiable Credentials with JSON payloads (SD-JWT VC)
draft-terbu-sd-jwt-vc-02
Abstract
This specification describes data formats as well as validation and
processing rules to express Verifiable Credentials with JSON payload
based on the SD-JWT format [I-D.ietf-oauth-selective-disclosure-jwt].
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 27 November 2023.
Copyright Notice
Copyright (c) 2023 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 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.
Terbu & Fett Expires 27 November 2023 [Page 1]
Internet-Draft SD-JWT VC May 2023
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Three-Party-Model . . . . . . . . . . . . . . . . . . . . 2
1.2. Rationale . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3. Requirements Notation and Conventions . . . . . . . . . . 4
1.4. Terms and Definitions . . . . . . . . . . . . . . . . . . 4
2. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Verifiable Credentials based on SD-JWT . . . . . . . . . . . 5
4.1. Media Type . . . . . . . . . . . . . . . . . . . . . . . 5
4.2. Data Format . . . . . . . . . . . . . . . . . . . . . . . 5
4.2.1. Header Parameters . . . . . . . . . . . . . . . . . . 6
4.2.2. Claims . . . . . . . . . . . . . . . . . . . . . . . 6
4.3. Example . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.4. Verification and Processing . . . . . . . . . . . . . . . 12
5. JWT Issuer Metadata . . . . . . . . . . . . . . . . . . . . . 13
5.1. JWT Issuer Metadata Request . . . . . . . . . . . . . . . 13
5.2. JWT Issuer Metadata Response . . . . . . . . . . . . . . 13
5.3. JWT Issuer Metadata Validation . . . . . . . . . . . . . 15
6. Presenting Verifiable Credentials . . . . . . . . . . . . . . 15
6.1. Data Format . . . . . . . . . . . . . . . . . . . . . . . 15
6.1.1. Holder Binding JWT . . . . . . . . . . . . . . . . . 16
6.2. Examples . . . . . . . . . . . . . . . . . . . . . . . . 16
6.3. Verification and Processing . . . . . . . . . . . . . . . 18
7. Security Considerations . . . . . . . . . . . . . . . . . . . 18
8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 18
9. Relationships to Other Documents . . . . . . . . . . . . . . 18
10. Normative References . . . . . . . . . . . . . . . . . . . . 18
11. Informative References . . . . . . . . . . . . . . . . . . . 19
Appendix A. IANA Considerations . . . . . . . . . . . . . . . . 19
A.1. JSON Web Token Claims Registration . . . . . . . . . . . 19
A.2. Media Types Registry . . . . . . . . . . . . . . . . . . 19
A.2.1. application/vc+sd-jwt . . . . . . . . . . . . . . . . 19
Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 20
Appendix C. Document History . . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
1. Introduction
1.1. Three-Party-Model
In the so-called Three-Party-Model, Issuers issue Verifiable
Credentials to a Holder, who can then present the Verifiable
Credentials to Verifiers. Verifiable Credentials are
cryptographically signed statements about a Subject, typically the
Holder.
Terbu & Fett Expires 27 November 2023 [Page 2]
Internet-Draft SD-JWT VC May 2023
+------------+
| |
| Issuer |
| |
+------------+
|
Issues Verifiable Credential
|
v
+------------+
| |
| Holder |
| |
+------------+
|
Presents Verifiable Credential
|
v
+-------------+
| |+ +------------+
| Verifiers ||+ | Status |
| |||----- optionally ------->| Provider |
+-------------+|| retrieve status of | |
+-------------+| Verifiable Credential +------------+
+-------------+
Figure 1: Three-Party-Model with optional Status Provider
Verifiers can check the authenticity of the data in the Verifiable
Credentials and optionally enforce Holder Binding, i.e., ask the
Holder to prove that they are the intended holder of the Verifiable
Credential, for example, by proving possession of a cryptographic key
referenced in the credential. This process is further described in
[I-D.ietf-oauth-selective-disclosure-jwt].
To support revocation of Verifiable Credentials, an optional fourth
party can be involved, a Status Provider, who delivers revocation
information to Verifiers. (The Verifier can also serve as the Status
Provider.)
This specification defines Verifiable Credentials based on the SD-JWT
format with a JWT Claim Set.
Terbu & Fett Expires 27 November 2023 [Page 3]
Internet-Draft SD-JWT VC May 2023
1.2. Rationale
JSON Web Tokens (JWTs) [RFC7519] can in principle be used to express
Verifiable Credentials in a way that is easy to understand and
process as it builds upon established web primitives. While JWT-
based credentials enable selective disclosure, i.e., the ability for
a Holder to disclose only a subset of the contained claims, in an
Identity Provider ecosystem by issuing new JWTs to the Verifier for
every presentation, this approach does not work in the three-party-
model.
Selective Disclosure JWT (SD-JWT)
[I-D.ietf-oauth-selective-disclosure-jwt] is a specification that
introduces conventions to support selective disclosure for JWTs: For
an SD-JWT document, a Holder can decide which claims to release
(within bounds defined by the Issuer). This format is therefore
perfectly suited for Verifiable Credentials.
SD-JWT itself does not define the claims that must be used within the
payload or their semantics. This specification therefore defines how
Verifiable Credentials can be expressed using SD-JWT.
JWTs (and SD-JWTs) can contain claims that are registered in "JSON
Web Token Claims" registry as defined in [RFC7519], as well as public
and private claims. Private claims are not relevant for this
specification due to the openness of the three-party-model. Since
SD-JWTs are based on JWTs, this specification aims to express the
basic Verifiable Credential data model purely through JWT Claim Sets,
using registered claims while allowing Issuers to use additional
registered claims, as well as new or existing public claims, to make
statements about the Subject of the Verifiable Credential.
1.3. Requirements Notation and Conventions
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 RFC
2119 [RFC2119].
1.4. Terms and Definitions
This specification uses the terms "Holder", "Issuer", "Verifier",
defined by [I-D.ietf-oauth-selective-disclosure-jwt].
Verifiable Credential (VC): An Issuer-signed assertion with claims
about a Subject.
SD-JWT-based Verifiable Credential (SD-JWT VC): A Verifiable
Terbu & Fett Expires 27 November 2023 [Page 4]
Internet-Draft SD-JWT VC May 2023
Credential encoded using the Issuance format defined in
[I-D.ietf-oauth-selective-disclosure-jwt].
Unsecured payload of an SD-JWT VC: A JSON object containing all
selectively disclosable and non-selectively disclosable claims of
the SD-JWT VC. The unsecured payload acts as the input JSON
object to issue an SD-JWT VC complying to this specification.
Status Provider: An entity that provides status information (e.g.
revocation) about a Verifiable Credential.
2. Scope
* This specification defines
- Data model and media types for Verifiable Credentials based on
SD-JWTs.
- Validation and processing rules for Verifiers and Holders.
3. Use Cases
TBD: explain use cases of the three-party-model.
TBD: conventional crypt, hardware security, hsm, mobile secure area,
compliance with FIPS
4. Verifiable Credentials based on SD-JWT
This section defines encoding, validation and processing rules for
SD-JWT VCs.
4.1. Media Type
SD-JWT VCs compliant with this specification MUST use the media type
application/vc+sd-jwt as defined in Appendix A.2.1.
4.2. Data Format
SD-JWT VCs MUST be encoded using the SD-JWT Combined Format for
Issuance as defined in Section 5.3. of
[I-D.ietf-oauth-selective-disclosure-jwt].
SD-JWT VCs MUST contain all Disclosures corresponding to their SD-JWT
component except for Decoy Digests as per Section 5.1.1.3. of
[I-D.ietf-oauth-selective-disclosure-jwt].
Terbu & Fett Expires 27 November 2023 [Page 5]
Internet-Draft SD-JWT VC May 2023
4.2.1. Header Parameters
This section defines JWT header parameters for the SD-JWT component
of the SD-JWT VC.
The typ header parameter of the SD-JWT MUST be present. The typ
value MUST use vc+sd-jwt. This indicates that the payload of the SD-
JWT contains plain JSON and follows the rules as defined in this
specification. It further indicates that the SD-JWT is a SD-JWT
component of a SD-JWT VC.
The following is a non-normative example of a decoded SD-JWT header:
{
"alg": "ES256",
"typ": "vc+sd-jwt"
}
4.2.2. Claims
This section defines the claims that can be included in the payload
of SD-JWT VCs.
4.2.2.1. type claim
This specification defines the JWT claim type. The type claim is
used to express the type of the JSON object that is secured by the
JWT. The type value MUST be a case-sensitive StringOrURI value.
The following is a non-normative example of how type is used to
express a type:
{
"type": "SomeType"
}
4.2.2.2. Registered JWT Claims
SD-JWT VCs MAY use any claim registered in the "JSON Web Token
Claims" registry as defined in [RFC7519].
If present, the following registered JWT claims MUST be included in
the SD-JWT and MUST NOT be included in the Disclosures, i.e. cannot
be selectively disclosed:
* iss
Terbu & Fett Expires 27 November 2023 [Page 6]
Internet-Draft SD-JWT VC May 2023
- REQUIRED. The Issuer of the Verifiable Credential. The value
of iss MUST be a URI. See [RFC7519] for more information.
* iat
- REQUIRED. The time of issuance of the Verifiable Credential.
See [RFC7519] for more information.
* nbf
- OPTIONAL. The time before which the Verifiable Credential MUST
NOT be accepted before validating. See [RFC7519] for more
information.
* exp
- OPTIONAL. The expiry time of the Verifiable Credential after
which the Verifiable Credential is no longer valid. See
[RFC7519] for more information.
* cnf
- REQUIRED when Cryptographic Holder Binding is to be supported.
Contains the confirmation method as defined in [RFC7800]. It
SHOULD contain a JWK as defined in Section 3.2 of [RFC7800] and
in this case, the kid (Key ID) member MUST be present in the
JWK. For Cryptographic Holder Binding, the Holder Binding JWT
in the Combined Format for Presentation MUST be signed by the
key identified in this claim.
* type
- REQUIRED. The type of the Verifiable Credential, e.g.,
IdentityCredential, as defined in Section 4.2.2.1.
* status
- OPTIONAL. The information on how to read the status of the
Verifiable Credential. See [TBD] for more information.
The following registered JWT claims MAY be contained in the SD-JWT or
in the Disclosures and MAY be selectively disclosed:
* sub
Terbu & Fett Expires 27 November 2023 [Page 7]
Internet-Draft SD-JWT VC May 2023
- OPTIONAL. The identifier of the Subject of the Verifiable
Credential. The value of sub MUST be a URI. The Issuer MAY
use it to provide the Subject identifier known by the Issuer.
There is no requirement for a binding to exist between sub and
cnf claims.
4.2.2.3. Public JWT claims
Additional public claims MAY be used in SD-JWT VCs depending on the
application.
4.3. Example
The following is a non-normative example of an unsecured payload of
an SD-JWT VC.
{
"type": "IdentityCredential",
"given_name": "John",
"family_name": "Doe",
"email": "johndoe@example.com",
"phone_number": "+1-202-555-0101",
"address": {
"street_address": "123 Main St",
"locality": "Anytown",
"region": "Anystate",
"country": "US"
},
"birthdate": "1940-01-01",
"is_over_18": true,
"is_over_21": true,
"is_over_65": true
}
The following is a non-normative example of how the unsecured payload
of the SD-JWT VC above can be used in a SD-JWT where the resulting
SD-JWT VC contains only claims about the Subject that are selectively
disclosable:
Terbu & Fett Expires 27 November 2023 [Page 8]
Internet-Draft SD-JWT VC May 2023
{
"_sd": [
"09vKrJMOlyTWM0sjpu_pdOBVBQ2M1y3KhpH515nXkpY",
"2rsjGbaC0ky8mT0pJrPioWTq0_daw1sX76poUlgCwbI",
"EkO8dhW0dHEJbvUHlE_VCeuC9uRELOieLZhh7XbUTtA",
"IlDzIKeiZdDwpqpK6ZfbyphFvz5FgnWa-sN6wqQXCiw",
"JzYjH4svliH0R3PyEMfeZu6Jt69u5qehZo7F7EPYlSE",
"PorFbpKuVu6xymJagvkFsFXAbRoc2JGlAUA2BA4o7cI",
"TGf4oLbgwd5JQaHyKVQZU9UdGE0w5rtDsrZzfUaomLo",
"jdrTE8YcbY4EifugihiAe_BPekxJQZICeiUQwY9QqxI",
"jsu9yVulwQQlhFlM_3JlzMaSFzglhQG0DpfayQwLUK4"
],
"iss": "https://example.com/issuer",
"iat": 1683000000,
"exp": 1883000000,
"type": "IdentityCredential",
"_sd_alg": "sha-256",
"cnf": {
"jwk": {
"kty": "EC",
"crv": "P-256",
"x": "TCAER19Zvu3OHF4j4W4vfSVoHIP1ILilDls7vCeGemc",
"y": "ZxjiWWbZMQGHVWKVQ4hbSIirsVfuecCE6t4jT9F2HZQ"
}
}
}
Note that a cnf claim has been added to the SD-JWT payload to express
the confirmation method of the holder binding.
The following are the Disclosures belonging to the SD-JWT payload
above:
*Claim given_name:*
* SHA-256 Hash: jsu9yVulwQQlhFlM_3JlzMaSFzglhQG0DpfayQwLUK4
* Disclosure:
WyIyR0xDNDJzS1F2ZUNmR2ZyeU5STjl3IiwgImdpdmVuX25hbWUiLCAiSm9o
biJd
* Contents: ["2GLC42sKQveCfGfryNRN9w", "given_name", "John"]
*Claim family_name:*
* SHA-256 Hash: TGf4oLbgwd5JQaHyKVQZU9UdGE0w5rtDsrZzfUaomLo
Terbu & Fett Expires 27 November 2023 [Page 9]
Internet-Draft SD-JWT VC May 2023
* Disclosure:
WyJlbHVWNU9nM2dTTklJOEVZbnN4QV9BIiwgImZhbWlseV9uYW1lIiwgIkRv
ZSJd
* Contents: ["eluV5Og3gSNII8EYnsxA_A", "family_name", "Doe"]
*Claim email:*
* SHA-256 Hash: JzYjH4svliH0R3PyEMfeZu6Jt69u5qehZo7F7EPYlSE
* Disclosure:
WyI2SWo3dE0tYTVpVlBHYm9TNXRtdlZBIiwgImVtYWlsIiwgImpvaG5kb2VA
ZXhhbXBsZS5jb20iXQ
* Contents: ["6Ij7tM-a5iVPGboS5tmvVA", "email",
"johndoe@example.com"]
*Claim phone_number:*
* SHA-256 Hash: PorFbpKuVu6xymJagvkFsFXAbRoc2JGlAUA2BA4o7cI
* Disclosure:
WyJlSThaV205UW5LUHBOUGVOZW5IZGhRIiwgInBob25lX251bWJlciIsICIr
MS0yMDItNTU1LTAxMDEiXQ
* Contents: ["eI8ZWm9QnKPpNPeNenHdhQ", "phone_number",
"+1-202-555-0101"]
*Claim address:*
* SHA-256 Hash: IlDzIKeiZdDwpqpK6ZfbyphFvz5FgnWa-sN6wqQXCiw
* Disclosure:
WyJRZ19PNjR6cUF4ZTQxMmExMDhpcm9BIiwgImFkZHJlc3MiLCB7InN0cmVl
dF9hZGRyZXNzIjogIjEyMyBNYWluIFN0IiwgImxvY2FsaXR5IjogIkFueXRv
d24iLCAicmVnaW9uIjogIkFueXN0YXRlIiwgImNvdW50cnkiOiAiVVMifV0
* Contents: ["Qg_O64zqAxe412a108iroA", "address", {"street_address":
"123 Main St", "locality": "Anytown", "region": "Anystate",
"country": "US"}]
*Claim birthdate:*
* SHA-256 Hash: jdrTE8YcbY4EifugihiAe_BPekxJQZICeiUQwY9QqxI
* Disclosure:
WyJBSngtMDk1VlBycFR0TjRRTU9xUk9BIiwgImJpcnRoZGF0ZSIsICIxOTQw
LTAxLTAxIl0
Terbu & Fett Expires 27 November 2023 [Page 10]
Internet-Draft SD-JWT VC May 2023
* Contents: ["AJx-095VPrpTtN4QMOqROA", "birthdate", "1940-01-01"]
*Claim is_over_18:*
* SHA-256 Hash: 09vKrJMOlyTWM0sjpu_pdOBVBQ2M1y3KhpH515nXkpY
* Disclosure:
WyJQYzMzSk0yTGNoY1VfbEhnZ3ZfdWZRIiwgImlzX292ZXJfMTgiLCB0cnVl
XQ
* Contents: ["Pc33JM2LchcU_lHggv_ufQ", "is_over_18", true]
*Claim is_over_21:*
* SHA-256 Hash: 2rsjGbaC0ky8mT0pJrPioWTq0_daw1sX76poUlgCwbI
* Disclosure:
WyJHMDJOU3JRZmpGWFE3SW8wOXN5YWpBIiwgImlzX292ZXJfMjEiLCB0cnVl
XQ
* Contents: ["G02NSrQfjFXQ7Io09syajA", "is_over_21", true]
*Claim is_over_65:*
* SHA-256 Hash: EkO8dhW0dHEJbvUHlE_VCeuC9uRELOieLZhh7XbUTtA
* Disclosure:
WyJsa2x4RjVqTVlsR1RQVW92TU5JdkNBIiwgImlzX292ZXJfNjUiLCB0cnVl
XQ
* Contents: ["lklxF5jMYlGTPUovMNIvCA", "is_over_65", true]
The SD-JWT and the Disclosures would then be serialized by the Issuer
into the following format for issuance to the Holder:
Terbu & Fett Expires 27 November 2023 [Page 11]
Internet-Draft SD-JWT VC May 2023
eyJhbGciOiAiRVMyNTYifQ.eyJfc2QiOiBbIjA5dktySk1PbHlUV00wc2pwdV9wZE9CV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.L67RXASLpGi_87_yukqvXGoSgarNxDIlu9M7aSK5rWObaN08Y
ERCxlP7CY8eTjFkHMVWRqnFLdpDdebBzmRXiA~WyIyR0xDNDJzS1F2ZUNmR2ZyeU5STj
l3IiwgImdpdmVuX25hbWUiLCAiSm9obiJd~WyJlbHVWNU9nM2dTTklJOEVZbnN4QV9BI
iwgImZhbWlseV9uYW1lIiwgIkRvZSJd~WyI2SWo3dE0tYTVpVlBHYm9TNXRtdlZBIiwg
ImVtYWlsIiwgImpvaG5kb2VAZXhhbXBsZS5jb20iXQ~WyJlSThaV205UW5LUHBOUGVOZ
W5IZGhRIiwgInBob25lX251bWJlciIsICIrMS0yMDItNTU1LTAxMDEiXQ~WyJRZ19PNj
R6cUF4ZTQxMmExMDhpcm9BIiwgImFkZHJlc3MiLCB7InN0cmVldF9hZGRyZXNzIjogIj
EyMyBNYWluIFN0IiwgImxvY2FsaXR5IjogIkFueXRvd24iLCAicmVnaW9uIjogIkFueX
N0YXRlIiwgImNvdW50cnkiOiAiVVMifV0~WyJBSngtMDk1VlBycFR0TjRRTU9xUk9BIi
wgImJpcnRoZGF0ZSIsICIxOTQwLTAxLTAxIl0~WyJQYzMzSk0yTGNoY1VfbEhnZ3ZfdW
ZRIiwgImlzX292ZXJfMTgiLCB0cnVlXQ~WyJHMDJOU3JRZmpGWFE3SW8wOXN5YWpBIiw
gImlzX292ZXJfMjEiLCB0cnVlXQ~WyJsa2x4RjVqTVlsR1RQVW92TU5JdkNBIiwgImlz
X292ZXJfNjUiLCB0cnVlXQ
4.4. Verification and Processing
The recipient of the SD-JWT VC MUST process and verify an SD-JWT VC
as follows:
1. REQUIRED. Process and verify the SD-JWT as defined in Section 6.
of [I-D.ietf-oauth-selective-disclosure-jwt]. For the
verification, the iss claim in the SD-JWT MAY be used to retrieve
the public key from the JWT Issuer Metadata configuration (as
defined in Section 5) of the SD-JWT VC issuer. A Verifier MAY
use alternative methods to obtain the public key to verify the
signature of the SD-JWT.
2. OPTIONAL. If status is present in the verified payload of the
SD-JWT, the status SHOULD be checked. It depends on the Verifier
policy to reject or accept a presentation of a SD-JWT VC based on
the status of the Verifiable Credential.
Any claims used that are not understood MUST be ignored.
Terbu & Fett Expires 27 November 2023 [Page 12]
Internet-Draft SD-JWT VC May 2023
Additional validation rules MAY apply, but their use is out of the
scope of this specification.
5. JWT Issuer Metadata
This specification defines the JWT Issuer Metadata to retrieve the
JWT Issuer Metadata configuration of the JWT Issuer of the JWT. The
JWT Issuer is identified by the iss claim in the JWT. Use of the JWT
Issuer Metadata is OPTIONAL.
JWT Issuers publishing JWT Issuer Metadata MUST make a JWT Issuer
Metadata configuration available at the path formed by concatenating
the string /.well-known/jwt-issuer to the iss claim value in the JWT.
The iss MUST be a case-sensitive URL using the HTTPS scheme that
contains scheme, host and, optionally, port number and path
components, but no query or fragment components.
5.1. JWT Issuer Metadata Request
A JWT Issuer Metadata configuration MUST be queried using an HTTP GET
request at the path defined in Section 5.
The following is a non-normative example of a HTTP request for the
JWT Issuer Metadata configuration when iss is set to
https://example.com:
GET /.well-known/jwt-issuer HTTP/1.1
Host: example.com
If the iss value contains a path component, any terminating / MUST be
removed before inserting /.well-known/ and the well-known URI suffix
between the host component and the path component.
The following is a non-normative example of a HTTP request for the
JWT Issuer Metadata configuration when iss is set to
https://example.com/user/1234:
GET /.well-known/jwt-issuer/user/1234 HTTP/1.1
Host: example.com
5.2. JWT Issuer Metadata Response
A successful response MUST use the 200 OK HTTP and return the JWT
Issuer Metadata configuration using the application/json content
type.
An error response uses the applicable HTTP status code value.
Terbu & Fett Expires 27 November 2023 [Page 13]
Internet-Draft SD-JWT VC May 2023
This specification defines the following JWT Issuer Metadata
configuration parameters:
* issuer REQUIRED. The JWT Issuer identifier, which MUST be
identical to the iss value in the JWT.
* jwks_uri
- OPTIONAL. URL string referencing the JWT Issuer's JSON Web Key
(JWK) Set [RFC7517] document which contains the JWT Issuer's
public keys. The value of this field MUST point to a valid JWK
Set document. Use of this parameter is RECOMMENDED, as it
allows for easy key rotation.
* jwks
- OPTIONAL. JWT Issuer's JSON Web Key Set [RFC7517] document
value, which contains the JWT Issuer's public keys. The value
of this field MUST be a JSON object containing a valid JWK Set.
This parameter is intended to be used by JWT Issuer that cannot
use the jwks_uri parameter.
JWT Issuer Metadata MUST include either jwks_uri or jwks in their JWT
Issuer Metadata, but not both.
It is RECOMMENDED that the JWT contains a kid JWT header parameter
that can be used to lookup the public key in the JWK Set included by
value or referenced in the JWT Issuer Metadata.
The following is a non-normative example of a JWT Issuer Metadata
configuration including jwks:
Terbu & Fett Expires 27 November 2023 [Page 14]
Internet-Draft SD-JWT VC May 2023
{
"issuer":"https://example.com",
"jwks":{
"keys":[
{
"kid":"doc-signer-05-25-2022",
"e":"AQAB",
"n":"nj3YJwsLUFl9BmpAbkOswCNVx17Eh9wMO-_AReZwBqfaWFcfG
HrZXsIV2VMCNVNU8Tpb4obUaSXcRcQ-VMsfQPJm9IzgtRdAY8NN8Xb7PEcYyk
lBjvTtuPbpzIaqyiUepzUXNDFuAOOkrIol3WmflPUUgMKULBN0EUd1fpOD70p
RM0rlp_gg_WNUKoW1V-3keYUJoXH9NztEDm_D2MQXj9eGOJJ8yPgGL8PAZMLe
2R7jb9TxOCPDED7tY_TU4nFPlxptw59A42mldEmViXsKQt60s1SLboazxFKve
qXC_jpLUt22OC6GUG63p-REw-ZOr3r845z50wMuzifQrMI9bQ",
"kty":"RSA"
}
]
}
}
The following is a non-normative example of a JWT Issuer Metadata
configuration including jwks_uri:
{
"issuer":"https://example.com",
"jwks_uri":"https://jwt-issuer.example.org/my_public_keys.jwks"
}
Additional JWT Issuer Metadata configuration parameters MAY also be
used.
5.3. JWT Issuer Metadata Validation
The issuer value returned MUST be identical to the iss value of the
JWT. If these values are not identical, the data contained in the
response MUST NOT be used.
6. Presenting Verifiable Credentials
This section defines encoding, validation and processing rules for
presentations of SD-JWT VCs.
6.1. Data Format
A presentation of an SD-JWT VC MUST be encoded using the SD-JWT
Combined Format for Presentation as defined in Section 5.4. of
[I-D.ietf-oauth-selective-disclosure-jwt].
Terbu & Fett Expires 27 November 2023 [Page 15]
Internet-Draft SD-JWT VC May 2023
A presentation of an SD-JWT VC MAY contain a Holder Binding JWT as
described in Section 5.4.1. of
[I-D.ietf-oauth-selective-disclosure-jwt].
6.1.1. Holder Binding JWT
If the presentation of the SD-JWT VC includes a Holder Binding JWT,
the following claims are used within the Holder Binding JWT:
* nonce
- REQUIRED. String value used to associate a transaction between
a Verifier an a Holder, and to mitigate replay attacks. The
value is passed through unmodified from the Verifier to the
Holder Binding JWT. Sufficient entropy MUST be present in the
nonce values used to prevent attackers from guessing values.
* aud
- REQUIRED. The intended recipient of the Holder Binding JWT
which is typically the Verifier. See [RFC7519] for more
information.
* iat
- REQUIRED. The time of issuance of the Holder Binding JWT. See
[RFC7519] for more information.
* exp
- OPTIONAL. The expiration time of the signature when the Holder
Binding is no longer considered valid. See [RFC7519] for more
information.
The Holder Binding JWT MAY include addtional claims which when not
understood MUST be ignored.
6.2. Examples
The following is a non-normative example of a presentation of the SD-
JWT shown above including a Holder Binding JWT:
Terbu & Fett Expires 27 November 2023 [Page 16]
Internet-Draft SD-JWT VC May 2023
eyJhbGciOiAiRVMyNTYifQ.eyJfc2QiOiBbIjA5dktySk1PbHlUV00wc2pwdV9wZE9CV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.L67RXASLpGi_87_yukqvXGoSgarNxDIlu9M7aSK5rWObaN08Y
ERCxlP7CY8eTjFkHMVWRqnFLdpDdebBzmRXiA~WyJRZ19PNjR6cUF4ZTQxMmExMDhpcm
9BIiwgImFkZHJlc3MiLCB7InN0cmVldF9hZGRyZXNzIjogIjEyMyBNYWluIFN0IiwgIm
xvY2FsaXR5IjogIkFueXRvd24iLCAicmVnaW9uIjogIkFueXN0YXRlIiwgImNvdW50cn
kiOiAiVVMifV0~eyJhbGciOiAiRVMyNTYifQ.eyJub25jZSI6ICIxMjM0NTY3ODkwIiw
gImF1ZCI6ICJodHRwczovL2V4YW1wbGUuY29tL3ZlcmlmaWVyIiwgImlhdCI6IDE2ODU
xMTE1Mzd9.jdNe3k5EOFyuBNsjvAkgXbsjTOAcZ9665m2hHGgrGvjKweCN-1a06JSAQm
0CFZx_DbP9i6WE0E95K45YK8QBMg
In this presentation, the Holder provides only the Disclosure for the
claim address. Other claims are not disclosed to the Verifier.
The following example shows a presentation of a (different) SD-JWT
without a Holder Binding JWT:
eyJhbGciOiAiRVMyNTYifQ.eyJfc2QiOiBbIjA5dktySk1PbHlUV00wc2pwdV9wZE9CV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.rf93MqgpquQAGwuMABOC34xknjRrZ9D6BPMJpQtHgkh_eL
F9saJ2lOIbGMnroAVIVLw3XL5ZCkaryeZPtaMAcg~WyJRZ19PNjR6cUF4ZTQxMmExMDh
pcm9BIiwgImFkZHJlc3MiLCB7InN0cmVldF9hZGRyZXNzIjogIjEyMyBNYWluIFN0Iiw
gImxvY2FsaXR5IjogIkFueXRvd24iLCAicmVnaW9uIjogIkFueXN0YXRlIiwgImNvdW5
0cnkiOiAiVVMifV0~
Terbu & Fett Expires 27 November 2023 [Page 17]
Internet-Draft SD-JWT VC May 2023
6.3. Verification and Processing
The Verifier MUST process and verify a presentation of SD-JWT VC as
follows:
1. REQUIRED. When processing and verifying the presentation of the
SD-JWT VC, the Verifier MUST follow the same verification and
processing rules as defined in Section 4.4.
2. OPTIONAL. If provided, the Verifier MUST verify the Holder
Binding JWT according to Section 6.2. of
[I-D.ietf-oauth-selective-disclosure-jwt]. To verify the Holder
Binding JWT, the cnf claim of the SD-JWT MUST be used.
7. Security Considerations
TBD: Verifier provided nonce.
8. Privacy Considerations
TBD: Holder provided nonce via jti.
9. Relationships to Other Documents
TBD
10. Normative References
[I-D.ietf-oauth-selective-disclosure-jwt]
Fett, D., Yasuda, K., and B. Campbell, "Selective
Disclosure for JWTs (SD-JWT)", Work in Progress, Internet-
Draft, draft-ietf-oauth-selective-disclosure-jwt-04, 11
April 2023, <https://datatracker.ietf.org/doc/html/draft-
ietf-oauth-selective-disclosure-jwt-04>.
[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>.
[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/info/rfc7519>.
[RFC7800] Jones, M., Bradley, J., and H. Tschofenig, "Proof-of-
Possession Key Semantics for JSON Web Tokens (JWTs)",
RFC 7800, DOI 10.17487/RFC7800, April 2016,
<https://www.rfc-editor.org/info/rfc7800>.
Terbu & Fett Expires 27 November 2023 [Page 18]
Internet-Draft SD-JWT VC May 2023
11. Informative References
[RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517,
DOI 10.17487/RFC7517, May 2015,
<https://www.rfc-editor.org/info/rfc7517>.
Appendix A. IANA Considerations
A.1. JSON Web Token Claims Registration
* Claim Name: "type"
- Claim Description: Credential Type
- Change Controller: IESG
- Specification Document(s): Section 4.2.2.1 of this document
A.2. Media Types Registry
A.2.1. application/vc+sd-jwt
The Internet media type for a SD-JWT VC is application/vc+sd-jwt.
Type name: : application
Subtype name: : vc+sd-jwt
Required parameters: : n/a
Optional parameters: : n/a
Encoding considerations: : 8-bit code points; SD-JWT VC values are
encoded as a series of base64url-encoded values (some of which may be
the empty string) separated by period ('.') and tilde ('~')
characters.
Security considerations: : See Security Considerations in Section 7.
Interoperability considerations: : n/a
* Published specification: : RFC TODO
* Applications that use this media type: : Applications that issue,
present, verify verifiable credentials and presentations.
* Additional information:
Terbu & Fett Expires 27 November 2023 [Page 19]
Internet-Draft SD-JWT VC May 2023
- Magic number(s): n/a
- File extension(s): n/a
- Macintosh file type code(s): n/a
- Person & email address to contact for further information: TBD
- Intended usage: COMMON
- Restrictions on usage: none
- Author: Oliver Terbu oliver.terbu@spruceid.com
(mailto:oliver.terbu@spruceid.com)
- Change controller: IETF
Appendix B. Acknowledgements
We would like to thank Alen Horvat, Andres Uribe, Christian Bormann,
Giuseppe De Marco, Paul Bastian, Torsten Lodderstedt, Tobias Looker
and Kristina Yasuda for their contributions (some of which
substantial) to this draft and to the initial set of implementations.
Appendix C. Document History
-02
* Adjusted terminology based on feedback
-01
* Removed W3C VCDM transformation algorithm
* Various editorial changes based on feedback
-00
* Initial Version
Authors' Addresses
Oliver Terbu
Spruce Systems, Inc.
Email: oliver.terbu@spruceid.com
Terbu & Fett Expires 27 November 2023 [Page 20]
Internet-Draft SD-JWT VC May 2023
Daniel Fett
Authlete Inc.
Email: mail@danielfett.de
Terbu & Fett Expires 27 November 2023 [Page 21]
