diff options
Diffstat (limited to 'cryptography/hazmat/primitives/cmac.py')
| -rw-r--r-- | cryptography/hazmat/primitives/cmac.py | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/cryptography/hazmat/primitives/cmac.py b/cryptography/hazmat/primitives/cmac.py index 7ae5c118..6f722031 100644 --- a/cryptography/hazmat/primitives/cmac.py +++ b/cryptography/hazmat/primitives/cmac.py @@ -15,10 +15,10 @@ from __future__ import absolute_import, division, print_function from cryptography import utils from cryptography.exceptions import ( - AlreadyFinalized, InvalidSignature, UnsupportedAlgorithm, _Reasons + AlreadyFinalized, UnsupportedAlgorithm, _Reasons ) from cryptography.hazmat.backends.interfaces import CMACBackend -from cryptography.hazmat.primitives import constant_time, interfaces +from cryptography.hazmat.primitives import interfaces @utils.register_interface(interfaces.MACContext) @@ -59,9 +59,11 @@ class CMAC(object): def verify(self, signature): if not isinstance(signature, bytes): raise TypeError("signature must be bytes.") - digest = self.finalize() - if not constant_time.bytes_eq(digest, signature): - raise InvalidSignature("Signature did not match digest.") + if self._ctx is None: + raise AlreadyFinalized("Context was already finalized.") + + ctx, self._ctx = self._ctx, None + ctx.verify(signature) def copy(self): if self._ctx is None: |