def _load_verification_key_from_encryption_context(self, algorithm,
encryption_context):
"""Loads the verification key from the encryption context if used by algorithm suite.
:param algorithm: Algorithm for which to generate signing key
:type algorithm: aws_encryption_sdk.identifiers.Algorithm
:param dict encryption_context: Encryption context from request
:returns: Raw verification key
:rtype: bytes
:raises SerializationError: if algorithm suite requires message signing and no verification key is found
"""
encoded_verification_key = encryption_context.get(
ENCODED_SIGNER_KEY, None)
if algorithm.signing_algorithm_info is not None and encoded_verification_key is None:
raise SerializationError(
"No signature verification key found in header for signed algorithm."
)
if algorithm.signing_algorithm_info is None:
if encoded_verification_key is not None:
raise SerializationError(
"Signature verification key found in header for non-signed algorithm."
)
return None
verifier = Verifier.from_encoded_point(
algorithm=algorithm, encoded_point=encoded_verification_key)
return verifier.key_bytes()
def test_verifier_from_encoded_point(
patch_default_backend, patch_serialization,
patch_ecc_public_numbers_from_compressed_point, patch_base64,
patch_build_hasher):
mock_point_instance = MagicMock()
mock_point_instance.public_key.return_value = sentinel.public_key
patch_ecc_public_numbers_from_compressed_point.return_value = mock_point_instance
patch_base64.b64decode.return_value = sentinel.compressed_point
algorithm = MagicMock()
verifier = Verifier.from_encoded_point(
algorithm=algorithm, encoded_point=sentinel.encoded_point)
patch_base64.b64decode.assert_called_once_with(sentinel.encoded_point)
algorithm.signing_algorithm_info.assert_called_once_with()
patch_ecc_public_numbers_from_compressed_point.assert_called_once_with(
curve=algorithm.signing_algorithm_info.return_value,
compressed_point=sentinel.compressed_point)
mock_point_instance.public_key.assert_called_once_with(
patch_default_backend.return_value)
assert isinstance(verifier, Verifier)
