Internet-Draft | SCRAPI | March 2024 |
Birkholz, et al. | Expires 5 September 2024 | [Page] |
This document describes a REST API that supports the normative requirements of the SCITT Architecture [I-D.draft-ietf-scitt-architecture]. Optional key discovery and query interfaces are provided to support interoperability issues with Decentralized Identifiers, X509 Certificates and Artifact Reposistories.¶
This note is to be removed before publishing as an RFC.¶
Status information for this document may be found at https://datatracker.ietf.org/doc/draft-ietf-scitt-scrapi/.¶
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Source for this draft and an issue tracker can be found at https://github.com/ietf-wg-scitt/draft-ietf-scitt-scrapi.¶
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The SCITT Architecture [I-D.draft-ietf-scitt-architecture] defines the core operations necessary to support supply chain transparency using COSE (CBOR Object Signing and Encryption).¶
Issuance of Signed Statements¶
Verification of Signed Statements¶
Registration of Signed Statements¶
Issuance of Receipts¶
Verification of Receipts¶
Production of Transparent Statements¶
Verification of Transparent Statements¶
In addition to defining concrete HTTP endpoints for these operations, this specification defines support for the following endpoints which support these operations:¶
Resolving Verification Keys for Issuers¶
Retrieving Receipts Asynchronously¶
Retrieving Signed Statements from an Artifact Repository¶
Retrieving Statements from an Artifact Repository¶
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.¶
This specification uses the terms "Signed Statement", "Receipt", "Transparent Statement", "Artifact Repositories", "Transparency Service", "Append-Only Log" and "Registration Policy" as defined in [I-D.draft-ietf-scitt-architecture].¶
Authentication is out of scope for this document. If Authentication is not implemented, rate limiting or other denial of service mititations MUST be applied to enable anonymous access.¶
NOTE: '' line wrapping per RFC 8792 in HTTP examples.¶
All messages are sent as HTTP GET or POST requests.¶
If the Transparency Service cannot process a client's request, it MUST return an HTTP 4xx or 5xx status code, and the body SHOULD be a JSON problem details object ([RFC7807]) containing:¶
type: A URI reference identifying the problem. To facilitate automated response to errors, this document defines a set of standard tokens for use in the type field within the URN namespace of: "urn:ietf:params:scitt:error:".¶
detail: A human-readable string describing the error that prevented the Transparency Service from processing the request, ideally with sufficient detail to enable the error to be rectified.¶
Error responses SHOULD be sent with the Content-Type: application/problem+json
HTTP header.¶
As an example, submitting a Signed Statement with an unsupported signature algorithm would return a 400 Bad Request
status code and the following body:¶
{ "type": "urn:ietf:params:scitt:error:badSignatureAlgorithm", "detail": "Signing algorithm not support" }¶
Most error types are specific to the type of request and are defined in the respective subsections below. The one exception is the "malformed" error type, which indicates that the Transparency Service could not parse the client's request because it did not comply with this document:¶
Error code: malformed
(The request could not be parsed).¶
Clients SHOULD treat 500 and 503 HTTP status code responses as transient failures and MAY retry the same request without modification at a later date.
Note that in the case of a 503 response, the Transparency Service MAY include a Retry-After
header field per [RFC7231] in order to request a minimum time for the client to wait before retrying the request.
In the absence of this header field, this document does not specify a minimum.¶
The following HTTP endpoints are mandatory to implement to enable conformance to this specification.¶
Authentication SHOULD NOT be implemented for this endpoint. This endpoint is used to discovery the capabilites of a transparency service implementing this specification.¶
Request:¶
Response:¶
Additional fields may be present. Fields that are not understood MUST be ignored.¶
Authentication MUST be implemented for this endpoint.¶
The following is a non-normative example of a HTTP request to register a Signed Statement:¶
Request:¶
POST /entries HTTP/1.1 Host: transparency.example Accept: application/json Content-Type: application/cose Payload (in CBOR diagnostic notation) 18([ / COSE Sign1 / h'a1013822', / Protected Header / {}, / Unprotected Header / null, / Detached Payload / h'269cd68f4211dffc...0dcb29c' / Signature / ])¶
The Registration Policy for the Transparency Service MUST be applied to the payload bytes, before any additional processing is performed.¶
If the payload
is detached, the Transparency Service depends on the authentication context of the client in the Registration Policy.
If the payload
is attached, the Transparency Service depends on both the authentication context of the client, and the verification of the Signed Statement in the Registration Policy.
The details of Registration Policy are out of scope for this document.¶
If registration succeeds the following identifier MAY be used to refer to the Signed Statement that was accepted:¶
urn:ietf:params:scitt:signed-statement:sha-256:base64url:5i6UeRzg1...qnGmr1o
¶
If the payload
was attached, or otherwise communicated to the Transparency Service, the following identifier MAY be used to refer to the payload
of the Signed Statement:¶
urn:ietf:params:scitt:statement:sha-256:base64url:5i6UeRzg1...qnGmr1o
¶
Response:¶
One of the following:¶
The response contains the Receipt for the Signed Statement. Fresh receipts may be requested through the resource identified in the Location header.¶
The response contains a reference to the receipt which will eventually be available for the Signed Statement.¶
If 202 is returned, then clients should wait until Registration succeeded or failed by polling the receipt endpoint using the receipt identifier returned in the response.¶
One of the following errors:¶
{ "type": "urn:ietf:params:scitt:error\ :signed-statement:algorithm-not-supported", "detail": \ "Signed Statement contained an algorithm that is not supported." }¶
{ "type": "urn:ietf:params:scitt:error\ :signed-statement:payload-missing", "detail": \ "Signed Statement payload must be attached (must be present)" }¶
{ "type": "urn:ietf:params:scitt:error\ :signed-statement:payload-forbidden", "detail": \ "Signed Statement payload must be detached (must not be present)" }¶
{ "type": "urn:ietf:params:scitt:error\ :signed-statement:rejected-by-registration-policy", "detail": \ "Signed Statement was not accepted by the current Registration Policy" }¶
{ "type": "urn:ietf:params:scitt:error\ :signed-statement:confirmation-missing", "detail": \ "Signed Statement did not contain proof of possession" }¶
TODO: other error codes¶
The following HTTP endpoints are optional to implement.¶
Authentication MUST be implemented for this endpoint.¶
This endpoint enables a Transparency Service to be an issuer of Signed Statements on behalf of authenticated clients. This supports cases where a client lacks the ability to perform complex cryptographic operations, but can be authenticated and report statements and measurements.¶
Request:¶
POST /signed-statements/issue HTTP/1.1 Host: transparency.example Accept: application/json Content-Type: application/vc+ld+json Payload { "@context": [ "https://www.w3.org/ns/credentials/v2", "https://www.w3.org/ns/credentials/examples/v2" ], "id": "https://transparency.example/credentials/1872", "type": ["VerifiableCredential", "SensorCredential"], "issuer": "https://transparency.example/device/1234", "validFrom": "2010-01-01T19:23:24Z", "credentialSubject": { "type": "Feature", "geometry": { "type": "Point", "coordinates": [125.6, 10.1] }, "properties": { "name": "Dinagat Islands" } } }¶
Response:¶
Authentication SHOULD be implemented for this endpoint.¶
This endpoint enables Transparency Service APIs to act like Artifact Repositories, and serve payload
values directly, instead of indirectly through Receipts.¶
Request:¶
Response:¶
Authentication SHOULD be implemented for this endpoint.¶
This endpoint enables Transparency Service APIs to act like Artifact Repositories, and serve Signed Statements directly, instead of indirectly through Receipts.¶
Request:¶
Response:¶
Authentication SHOULD be implemented for this endpoint.¶
Request:¶
Response:¶
If the Signed Statement requested is already included in the Append-Only Log:¶
If the Signed Statement requested is not yet included in the Append-Only Log:¶
Additional eventually consistent operation details MAY be present. Support for eventually consistent Receipts is implementation specific, and out of scope for this specification.¶
This endpoint is inspired by [I-D.draft-ietf-oauth-sd-jwt-vc]. Authentication SHOULD NOT be implemented for this endpoint. This endpoint is used to discover verification keys, which is the reason that authentication is not required.¶
The following is a non-normative example of a HTTP request for the Issuer Metadata configuration when iss
is set to https://transparency.example/tenant/1234
:¶
Request:¶
Response:¶
This endpoint in inspired by [I-D.draft-demarco-oauth-nonce-endpoint].¶
Authentication SHOULD NOT be implemented for this endpoint. This endpoint is used to demonstrate proof of posession, which is the reason that authentication is not required. Client holding signed statements that require demonstrating proof of possession MUST use this endpoint to obtain a nonce.¶
Request:¶
Response:¶
This endpoint enables the use of the DID Web Decentralized Identifier Method, as an alternative expression of the Issuer Metadata endpoint.¶
This endpoint is DEPRECATED.¶
The following is a non-normative example of a HTTP request for the Issuer Metadata configuration when iss
is set to did:web:transparency.example:tenant:1234
:¶
Request:¶
Response:¶
TODO¶
TODO: Consider negotiation for receipt as "JSON" or "YAML". TODO: Consider impact of media type on "Data URIs" and QR Codes.¶
IANA is requested to register the URN sub-namespace urn:ietf:params:scitt
in the "IETF URN Sub-namespace for Registered Protocol Parameter Identifiers"
Registry [IANA.params], following the template in [RFC3553]:¶
Registry name: scitt Specification: [RFCthis] Repository: http://www.iana.org/assignments/scitt Index value: No transformation needed.¶
The following value is requested to be registered in the "Well-Known URIs" registry (using the template from [RFC5785]):¶
URI suffix: issuer Change controller: IETF Specification document(s): RFCthis. Related information: N/A¶
The following value is requested to be registered in the "Well-Known URIs" registry (using the template from [RFC5785]):¶
URI suffix: transparency-configuration Change controller: IETF Specification document(s): RFCthis. Related information: N/A¶
TODO: Register them from here.¶
This section requests registration of the "application/scitt.receipt+cose" media type [RFC2046] in the "Media Types" registry in the manner described in [RFC6838].¶
To indicate that the content is a SCITT Receipt:¶
Type name: application¶
Subtype name: scitt.receipt+cose¶
Required parameters: n/a¶
Optional parameters: n/a¶
Encoding considerations: TODO¶
Security considerations: TODO¶
Interoperability considerations: n/a¶
Published specification: this specification¶
Applications that use this media type: TBD¶
Fragment identifier considerations: n/a¶
Additional information:¶
Person & email address to contact for further information: TODO¶
Intended usage: COMMON¶
Restrictions on usage: none¶
Author: TODO¶
Change Controller: IESG¶
Provisional registration? No¶