csrfx

var (
	// ErrCSRFMalformed indicates the token is not valid base64url or has the
	// wrong length/version.
	ErrCSRFMalformed = errors.New("csrfx: malformed token")
	// ErrCSRFExpired indicates the token's embedded expiry is in the past.
	ErrCSRFExpired = errors.New("csrfx: token expired")
	// ErrCSRFMismatch indicates the HMAC did not verify (tampered token or
	// wrong key) or the double-submit cookie/header pair did not match.
	ErrCSRFMismatch = errors.New("csrfx: token signature mismatch")
	// ErrCSRFSessionMismatch indicates the token was issued for a different
	// session than the one presenting it.
	ErrCSRFSessionMismatch = errors.New("csrfx: token session mismatch")
	// ErrCSRFUnbound indicates Verify was called with an empty sessionID.
	// Issue("") still mints a token bound to "" (used for the best-effort
	// pre-login /csrf mint, see api.go.tmpl) but Verify refuses to accept
	// ANY token — even one whose signature is otherwise valid — against an
	// empty session: every caller lacking a session would collapse onto the
	// same "" binding, making a pre-login-minted token replayable by anyone
	// who never authenticates (SEC-0061). Callers must resolve a real
	// session id (typically the verified JWT "sub") before Verify.
	ErrCSRFUnbound = errors.New("csrfx: token not bound to a session")
	// ErrKeyTooShort indicates the signing key is shorter than the 32-byte
	// minimum.
	ErrKeyTooShort = errors.New("csrfx: signing key must be at least 32 bytes")
)