def test_symmetric_mac(kid, alg, key_ops, base_iv, k, pl, algo, ct):
key = SymmetricKey(kid=kid, alg=alg, key_ops=key_ops, base_iv=base_iv, k=k)
assert ct == key.compute_tag(pl, algo)
# switch to another key operation
key.key_ops = KeyOps.MAC_VERIFY
assert key.verify_tag(ct, pl, algo)
def compute_tag(self,
key: SymmetricKey,
alg: Optional[CoseAlgorithms] = None) -> bytes:
""" Computes the authentication tag of a COSE_Mac or COSE_Mac0 message. """
if not isinstance(key, SymmetricKey):
raise CoseIllegalKeyType(
"COSE key should be of type 'SymmetricKey', got {}".format(
type(key)))
self.auth_tag = key.compute_tag(self._mac_structure, alg)
return self.auth_tag