internal/

Package canonical implements shared canonicalization rules — URL/URI canonicalization, JSON canonicalization where required for signature input, and parameter-ordering/normalization — so client, server and resource agree byte-for-byte on what they are signing, verifying or comparing.

Package clientassertion implements private_key_jwt-style client authentication: assertion construction and verification.

Package critical implements the "crit" (Critical) Header Parameter check RFC 7515 §4.1.11 (JWS) and RFC 7516 §4.1.13 (JWE, which inherits the JWS rule) both require: a header must be rejected only if "crit" names a parameter the recipient doesn't actually understand and process — every other unrecognized member is ignored, never rejected (RFC 7515 §4.2/§4.3, RFC 7516 §4.2/§4.3).

Package dpop implements DPoP (RFC 9449) proof creation and verification: proof JWT construction, the "ath" access-token hash, JWK thumbprint computation, and the checks needed to detect proof replay.

Package jarm implements JWT Secured Authorization Response Mode signing and verification: encoding the authorization response as a signed JWT and validating one on receipt.

Package jose implements the shared JWT/JWS/JWK parsing, encoding and signature-verification primitives used throughout the module: strict parsing, JWK validation, and algorithm-policy enforcement.

Package jwe implements JWE (RFC 7516) compact-serialization encryption and decryption for exactly the two key-management algorithms fapi.KeyManagementAlgorithm supports (RSA-OAEP-256 and ECDH-ES+A256KW), each of which may be paired with either content-encryption algorithm fapi.ContentEncryptionAlgorithm supports: A256GCM (a single AEAD primitive) or A256CBC-HS512 (encrypt-then-MAC — AES-256-CBC plus a separate HMAC-SHA-512 tag, RFC 7518 §5.2.3).

Package metadata implements shared parsing and validation for authorization-server and client metadata documents (OAuth 2.0 Authorization Server Metadata / OpenID Connect Discovery, and OAuth 2.0 Dynamic Client Registration metadata).

Package par implements the shared wire format for Pushed Authorization Requests (RFC 9126): request encoding, the request_uri response shape, and the parameter rules common to submitting and accepting a PAR request.

Package pkce implements PKCE (RFC 7636) code-verifier generation and code-challenge derivation/verification.

Package requestobject implements signed JAR (RFC 9101) request-object construction and verification for the parameters carried in an authorization/PAR request.

Package token implements shared JWT access token (RFC 9068) and ID token (OIDC Core) issuance and validation logic that sits below the public TokenSet/TokenResult types.

Package validation implements shared strict-parsing and input-validation helpers (bounded string/size checks, allow-listed character sets, redirect URI matching, scope syntax, and similar low-level checks used across role packages).