diff options
Diffstat (limited to 'cryptography/hazmat/primitives/hmac.py')
| -rw-r--r-- | cryptography/hazmat/primitives/hmac.py | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/cryptography/hazmat/primitives/hmac.py b/cryptography/hazmat/primitives/hmac.py index 1457ed78..08dfae01 100644 --- a/cryptography/hazmat/primitives/hmac.py +++ b/cryptography/hazmat/primitives/hmac.py @@ -15,13 +15,14 @@ from __future__ import absolute_import, division, print_function import six +from cryptography import utils +from cryptography.exceptions import AlreadyFinalized from cryptography.hazmat.primitives import interfaces -@interfaces.register(interfaces.HashContext) +@utils.register_interface(interfaces.HashContext) class HMAC(object): def __init__(self, key, algorithm, ctx=None, backend=None): - super(HMAC, self).__init__() if not isinstance(algorithm, interfaces.HashAlgorithm): raise TypeError("Expected instance of interfaces.HashAlgorithm.") self.algorithm = algorithm @@ -33,19 +34,30 @@ class HMAC(object): self._backend = backend self._key = key if ctx is None: - self._ctx = self._backend.hmacs.create_ctx(key, self.algorithm) + self._ctx = self._backend.create_hmac_ctx(key, self.algorithm) else: self._ctx = ctx def update(self, msg): + if self._ctx is None: + raise AlreadyFinalized("Context was already finalized") if isinstance(msg, six.text_type): raise TypeError("Unicode-objects must be encoded before hashing") - self._backend.hmacs.update_ctx(self._ctx, msg) + self._ctx.update(msg) def copy(self): - return self.__class__(self._key, self.algorithm, backend=self._backend, - ctx=self._backend.hmacs.copy_ctx(self._ctx)) + if self._ctx is None: + raise AlreadyFinalized("Context was already finalized") + return HMAC( + self._key, + self.algorithm, + backend=self._backend, + ctx=self._ctx.copy() + ) def finalize(self): - return self._backend.hmacs.finalize_ctx(self._ctx, - self.algorithm.digest_size) + if self._ctx is None: + raise AlreadyFinalized("Context was already finalized") + digest = self._ctx.finalize() + self._ctx = None + return digest |