def test_create_aes_ctr_hmac_streaming_key_template(self):
# Intentionally using 'weird' or invalid values for parameters,
# to test that the function correctly puts them in the resulting template.
template = None
with self.assertWarns(DeprecationWarning):
template = (
streaming_aead.streaming_aead_key_templates
.create_aes_ctr_hmac_streaming_key_template(
aes_key_size=42,
hkdf_hash_type=common_pb2.HashType.SHA1,
derived_key_size=76,
mac_hash_type=common_pb2.HashType.UNKNOWN_HASH,
tag_size=39,
ciphertext_segment_size=64,
))
self.assertEqual(
'type.googleapis.com/google.crypto.tink.AesCtrHmacStreamingKey',
template.type_url)
self.assertEqual(tink_pb2.RAW, template.output_prefix_type)
key_format = aes_ctr_hmac_streaming_pb2.AesCtrHmacStreamingKeyFormat()
key_format.ParseFromString(template.value)
self.assertEqual(42, key_format.key_size)
self.assertEqual(common_pb2.HashType.SHA1, key_format.params.hkdf_hash_type)
self.assertEqual(76, key_format.params.derived_key_size)
self.assertEqual(common_pb2.HashType.UNKNOWN_HASH,
key_format.params.hmac_params.hash)
self.assertEqual(39, key_format.params.hmac_params.tag_size)
self.assertEqual(64, key_format.params.ciphertext_segment_size)
def test_aes256_ctr_hmac_sha256_4kb(self):
template = streaming_aead_key_templates.AES256_CTR_HMAC_SHA256_4KB
self.assertEqual(
'type.googleapis.com/google.crypto.tink.AesCtrHmacStreamingKey',
template.type_url)
self.assertEqual(tink_pb2.RAW, template.output_prefix_type)
key_format = aes_ctr_hmac_streaming_pb2.AesCtrHmacStreamingKeyFormat()
key_format.ParseFromString(template.value)
self.assertEqual(32, key_format.key_size)
self.assertEqual(common_pb2.HashType.SHA256,
key_format.params.hkdf_hash_type)
self.assertEqual(32, key_format.params.derived_key_size)
self.assertEqual(common_pb2.HashType.SHA256,
key_format.params.hmac_params.hash)
self.assertEqual(32, key_format.params.hmac_params.tag_size)
self.assertEqual(4096, key_format.params.ciphertext_segment_size)
def create_aes_ctr_hmac_streaming_key_template(
aes_key_size: int, hkdf_hash_type: common_pb2.HashType,
derived_key_size: int, mac_hash_type: common_pb2.HashType,
tag_size: int, ciphertext_segment_size: int) -> tink_pb2.KeyTemplate:
"""Creates an AES CTR HMAC Streaming KeyTemplate, and fills in its values."""
key_format = aes_ctr_hmac_streaming_pb2.AesCtrHmacStreamingKeyFormat()
key_format.key_size = aes_key_size
key_format.params.ciphertext_segment_size = ciphertext_segment_size
key_format.params.derived_key_size = derived_key_size
key_format.params.hkdf_hash_type = hkdf_hash_type
key_format.params.hmac_params.hash = mac_hash_type
key_format.params.hmac_params.tag_size = tag_size
key_template = tink_pb2.KeyTemplate()
key_template.value = key_format.SerializeToString()
key_template.type_url = _AES_CTR_HMAC_STREAMING_KEY_TYPE_URL
key_template.output_prefix_type = tink_pb2.RAW
return key_template