hashers

var ErrHashMismatch = errors.New("hash mismatch")

var SHA512HexPattern = regexp.MustCompile(`^[0-9a-f]{128}$`)

SHA512HexPattern matches a SHA-512 digest as 128 lowercase hex characters, the form Doorkeeper stores (Digest::SHA512.hexdigest). A Doorkeeper plaintext is 64 hex chars (SecureRandom.hex(32)), so an accidentally-sent plaintext fails the match instead of being stored as a digest.