Struct PasetoV4PublicVerifier 

pub struct PasetoV4PublicVerifier { /* private fields */ }

PASETO v4.public verifier — checks signatures with an Ed25519 public key.

The edge-safe half of v4.public: a public key can verify a token but is physically unable to mint one. It is the only TokenVerifier in the cheers tree that doesn’t also carry minting power (the symmetric codecs in cheers-server are Codecs, so they do) — which is exactly what lets an edge (e.g. a CF Worker) authenticate sessions without the forge-any-session blast radius of holding a minting key. Pair with a cheers_server::PasetoV4SecretMinter at the origin.

Implementations

impl PasetoV4PublicVerifier

pub fn from_public_key( bytes: &[u8; 32], ) -> Result<PasetoV4PublicVerifier, CodecError>

Build from a 32-byte Ed25519 public key (the V4 public-key size).

pub fn from_key(public: AsymmetricPublicKey<V4>) -> PasetoV4PublicVerifier

Wrap an already-parsed Ed25519 public key — e.g. the half a minter derives from its secret key (cheers_server::PasetoV4SecretMinter::verifier).

pub fn public_key(&self) -> &AsymmetricPublicKey<V4>

The underlying public key, e.g. to serialize the 32 bytes for publishing to an edge.

pub fn verify_mcp_at( &self, token: &str, now: i64, expected_kid: &str, ) -> Result<McpClaims, CodecError>

Verify an MCP-call token signed by cheers_server::PasetoV4SecretMinter::mint_mcp, returning the embedded McpClaims.

Wire convention (R592-B7) — the shape kamaji-bin’s verifier, cheers-mock, and yubaba’s minter already share: claims is the token’s FLAT top-level JSON payload (no wrapping claim key), verified via pasetors’ LOW-LEVEL PublicToken::verify — never the high-level public::verify, which hard-rejects the i64 exp/iat this shape carries.

kid is REQUIRED in the PASETO footer: an empty footer is CodecError::MissingKid; a footer that doesn’t parse or has no kid field is CodecError::Malformed; a kid that doesn’t match expected_kid is CodecError::UnknownKid (this verifier holds a single trusted (kid, public key) pair — it has no JWKS of its own, so “does the footer’s kid match the one caller I trust” is the whole key-selection check here; a full JWKS lookup across many kids is a consumer’s job, e.g. kamaji-bin’s AuthVerifier).

Expiry is owned by McpClaims::is_expired_at (parity with the session-claim path) — exp <= now is CodecError::Expired. iss/aud are NOT checked here — that policy varies per consumer (which issuer/audience a caller expects), so it lives at the caller (e.g. cloud-admin’s viewer_from_claims), not in this shared primitive.

Trait Implementations

impl TokenVerifier for PasetoV4PublicVerifier

fn verify_at(&self, token: &str, now: i64) -> Result<Claims, CodecError>

Verify a token against now (unix seconds). Reject if expires_at <= now.

fn verify(&self, token: &str) -> Result<Claims, CodecError>

Convenience wrapper using the system clock.