Class CryptographyECKey

jose/backends/cryptography_backend.py:33–200

class CryptographyECKey(Key):
    SHA256 = hashes.SHA256
    SHA384 = hashes.SHA384
    SHA512 = hashes.SHA512

    def __init__(self, key, algorithm, cryptography_backend=default_backend):
        if algorithm not in ALGORITHMS.EC:
            raise JWKError("hash_alg: %s is not a valid hash algorithm" % algorithm)

        self.hash_alg = {
            ALGORITHMS.ES256: self.SHA256,
            ALGORITHMS.ES384: self.SHA384,
            ALGORITHMS.ES512: self.SHA512,
        }.get(algorithm)
        self._algorithm = algorithm

        self.cryptography_backend = cryptography_backend

        if hasattr(key, "public_bytes") or hasattr(key, "private_bytes"):
            self.prepared_key = key
            return

        if hasattr(key, "to_pem"):
            # convert to PEM and let cryptography below load it as PEM
            key = key.to_pem().decode("utf-8")

        if isinstance(key, dict):
            self.prepared_key = self._process_jwk(key)
            return

        if isinstance(key, str):
            key = key.encode("utf-8")

        if isinstance(key, bytes):
            # Attempt to load key. We don't know if it's
            # a Public Key or a Private Key, so we try
            # the Public Key first.
            try:
                try:
                    key = load_pem_public_key(key, self.cryptography_backend())
                except ValueError:
                    key = load_pem_private_key(key, password=None, backend=self.cryptography_backend())
            except Exception as e:
                raise JWKError(e)

            self.prepared_key = key
            return

        raise JWKError("Unable to parse an ECKey from key: %s" % key)

    def _process_jwk(self, jwk_dict):
        if not jwk_dict.get("kty") == "EC":
            raise JWKError("Incorrect key type. Expected: 'EC', Received: %s" % jwk_dict.get("kty"))

        if not all(k in jwk_dict for k in ["x", "y", "crv"]):
            raise JWKError("Mandatory parameters are missing")

        x = base64_to_long(jwk_dict.get("x"))