Verify hook signatures

Enroute signs hooks with Ed25519 HTTP Message Signatures (RFC 9421). Obtain the deployment public key and verify a request before reading its body.

Procedure

1. Parse Signature-Input. Enroute covers @method, @authority, @path, and content-digest.
2. Reject a created timestamp more than 300 seconds from the current time.
3. Select the public key by keyid; the key determines the algorithm.
4. Compute the body SHA-256 and compare it with the Content-Digest SHA-256 entry (RFC 9530).
5. Build the RFC 9421 signature base and verify Signature with Ed25519.

Use @authority and @path from the configured hook_endpoint_url, not the URL as delivered by a proxy. The configured authority includes a port only when the URL includes one.

keyid is the RFC 7638 JWK thumbprint of the public key. During rotation, accept both keys until all signers use the replacement.

Use an RFC 9421 library to parse and verify the signature, but independently check Content-Digest against the received bytes. The signature covers the digest header; a signature library does not validate the body for you.

Test vector

The local stack uses the RFC 9421 test-key-ed25519 key. For a POST with body hello to https://example.com/api/enroute/hooks and created=1700000000, it produces:

content-digest: sha-256=:LPJNul+wow4m6DsqxbninhsWHlwfp0JecwQzYpOLmCQ=:
signature-input: sig1=("@method" "@authority" "@path" "content-digest");created=1700000000;keyid="poqkLGiymh_W0uP6PZFw-dvez3QJT5SolqXBCW38r0U"
signature: sig1=:szerawmIvPHHZZJI/5wM+7a5l9CSpl34E2JgSeQFLfZIrF9MgJ28y7BGGG6sbYQineXZm83p3K3SKMkhu7g6DQ==:

Validate the vector with the library before using it in production.