diff options
Diffstat (limited to 'src/cryptography/hazmat/backends/commoncrypto/hashes.py')
-rw-r--r-- | src/cryptography/hazmat/backends/commoncrypto/hashes.py | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/src/cryptography/hazmat/backends/commoncrypto/hashes.py b/src/cryptography/hazmat/backends/commoncrypto/hashes.py new file mode 100644 index 00000000..217f4e8c --- /dev/null +++ b/src/cryptography/hazmat/backends/commoncrypto/hashes.py @@ -0,0 +1,64 @@ +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or +# implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +from __future__ import absolute_import, division, print_function + +from cryptography import utils +from cryptography.exceptions import UnsupportedAlgorithm, _Reasons +from cryptography.hazmat.primitives import interfaces + + +@utils.register_interface(interfaces.HashContext) +class _HashContext(object): + def __init__(self, backend, algorithm, ctx=None): + self._algorithm = algorithm + self._backend = backend + + if ctx is None: + try: + methods = self._backend._hash_mapping[self.algorithm.name] + except KeyError: + raise UnsupportedAlgorithm( + "{0} is not a supported hash on this backend.".format( + algorithm.name), + _Reasons.UNSUPPORTED_HASH + ) + ctx = self._backend._ffi.new(methods.ctx) + res = methods.hash_init(ctx) + assert res == 1 + + self._ctx = ctx + + algorithm = utils.read_only_property("_algorithm") + + def copy(self): + methods = self._backend._hash_mapping[self.algorithm.name] + new_ctx = self._backend._ffi.new(methods.ctx) + # CommonCrypto has no APIs for copying hashes, so we have to copy the + # underlying struct. + new_ctx[0] = self._ctx[0] + + return _HashContext(self._backend, self.algorithm, ctx=new_ctx) + + def update(self, data): + methods = self._backend._hash_mapping[self.algorithm.name] + res = methods.hash_update(self._ctx, data, len(data)) + assert res == 1 + + def finalize(self): + methods = self._backend._hash_mapping[self.algorithm.name] + buf = self._backend._ffi.new("unsigned char[]", + self.algorithm.digest_size) + res = methods.hash_final(buf, self._ctx) + assert res == 1 + return self._backend._ffi.buffer(buf)[:] |