Module jwt 

ES256 JWS signing — the one signing primitive the OAuth flow needs.

Two things are signed with the confidential client’s key:

• the client assertion (private_key_jwt), proving to the PDS’s token endpoint that we are the client named by client_id, and
• DPoP proofs, proving possession of the per-session DPoP key.

Both are compact JWS: base64url(header) . base64url(payload) . base64url(sig).

The detail worth stating, because getting it wrong produces a signature that verifies nowhere: JOSE ECDSA signatures are the fixed-width r || s form (64 bytes for P-256), not ASN.1 DER. A DER signature is the default output of many ECDSA APIs and is silently accepted by nothing.

Functions

sign

Sign header/claims as a compact ES256 JWS.

verify

Verify a compact ES256 JWS against key’s public half.