wimsey-httpsig

The WIMSE HTTP Message Signatures binding.

An RFC 9421 HTTP Message Signatures implementation and the WIMSE profile of it. The caller signs the outgoing request — including the header carrying its WIT — with its proof-of-possession key, so an intermediary can read the request but cannot alter anything the signature covers.

The RFC 9421 signature base is verified byte-for-byte against the worked example in Section 2.5, and verification reuses the received parameter substring verbatim rather than re-serializing it.

The WIMSE profile (Section 3 of the http-signature draft) narrows RFC 9421 considerably, and is enforced by opting in with VerifyConfig::wimse_profile:

• @method and @request-target must be covered, plus Content-Type, Content-Digest, Authorization, Txn-Token and Workload-Identity-Token whenever the message carries them;
• created, expires, nonce and tag are mandatory, with tag fixed to wimse-workload-to-workload;
• wimse-aud is mandatory on a request and names the service it is for;
• keyid and alg are forbidden — the key travels in the WIT, and its cnf JWK pins the algorithm.

Responses are signed the same way, with the profile's own rules: @status plus @method;req and @request-target;req, and wimse-req-nonce carrying back the nonce from the request being answered. Both bindings exist so that a signed response cannot be lifted onto a different request.

With the profile off, the crate is a plain RFC 9421 implementation.

Part of wimsey, a vendor-neutral reference implementation of the IETF WIMSE workload-identity drafts, in Rust.

Pre-alpha. The specs are Internet-Drafts, not RFCs. This crate pins one revision; see SPEC-MAP.md for the pin and for the requirements it does not yet meet.

All signing is EdDSA over Ed25519, which is deterministic, so output is byte-for-byte reproducible. Time is injected rather than read from a clock, so verification is reproducible too. Cross-implementation test vectors live in conformance/.

Licensed under Apache-2.0.