All notable changes to this project are documented here. The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[0.6.0] - 2026-06-21

Security

  • AttestoClient.Discovery hardens its discovery/JWKS fetches against SSRF: redirects are no longer followed (a 3xx surfaces as {:http_status, _} rather than being chased to its Location), and a URL whose host resolves to a loopback, private, link-local, or unique-local address is rejected with :blocked_host — so an attacker-influenced issuer/jwks_uri cannot point a server-side fetch at an internal service or the cloud metadata endpoint. An unresolvable host is left to the transport.

Added

  • AttestoClient.IDToken - verify OpenID Connect ID Tokens against authorization server JWKS/discovery, including issuer, audience, azp, expiration, issued-at, nonce, max_age/auth_time, and detached at_hash / c_hash / s_hash validation. Interop-tested against Attesto.IDToken.mint/4.
  • AttestoClient.IdentityAssertion - build Identity Assertion JWT Authorization Grant assertions (ID-JAG / EMA) with the oauth-id-jag+jwt header and the required iss/sub/aud/client_id/jti/iat/exp claims. Interop-tested against Attesto.IdentityAssertion.verify/3.
  • AttestoClient.PKCE - generate S256 PKCE verifier/challenge pairs, delegating challenge computation to Attesto.PKCE.challenge/1 so generated pairs verify under Attesto.PKCE.verify/3.
  • AttestoClient.SignedIntrospection - verify RFC 9701 signed token introspection responses against authorization-server JWKS/discovery. Interop-tested against Attesto.SignedIntrospection.response_jwt/4.
  • AttestoClient.UserInfo - verify signed OpenID Connect UserInfo JWT responses, including issuer/audience/subject checks and optional binding to a previously verified ID Token subject.
  • Internal AttestoClient.Verifier shared by the AS-signed JWT verifiers (not public API; hidden from docs).
  • AttestoClient.ClientAssertion - build private_key_jwt client authentication assertions (RFC 7523 / OpenID Connect Core §9), signed with the client's own key. Carries a cross-language parity test against an independent PyJWT reference verifier, plus in-family interop against Attesto.ClientAssertion.verify/5.
  • AttestoClient.RequestObject - build signed authorization request objects (JAR, RFC 9101 / FAPI 2.0 Message Signing §5.3.1): the caller's authorization parameters wrapped with the iss/aud/iat/nbf/exp/jti envelope and the oauth-authz-req+jwt typ, signed with the client's key. The lifetime is bounded to the FAPI 60-minute window. Parity-tested against an independent PyJWT reference and in-family against Attesto.RequestObject.verify/3 under the FAPI Message Signing policy.
  • Internal AttestoClient.Builder shared by the builders (not public API; hidden from docs).
  • AttestoClient.JARM - verify a signed authorization response (JARM, FAPI 2.0 Message Signing §5.4): JWS signature against the authorization server's JWKS (FAPI algorithm allow-list, none rejected, kid selection), plus iss/aud/ iat/exp, returning the response parameters. Parity-tested by verifying a JARM token signed by an independent PyJWT signer (the flipped external direction) and one signed by Attesto.JARM.response_jwt/4 (in-family).
  • AttestoClient.Discovery - fetch and read OAuth 2.0 / OpenID Connect authorization-server metadata and JWKS (RFC 8414 / OpenID Connect Discovery 1.0) over Req, with https and RFC 8414 §3.3 issuer-match validation. Verified in-family against Attesto.OpenIDDiscovery.metadata/2 output.

Changed

  • Require attesto ~> 0.9 so the client mirror can use the current ID Token, ID-JAG, PKCE, signed introspection, signing-algorithm, and hash primitives.