diff options
| -rw-r--r-- | cryptography/hazmat/primitives/ciphers/base.py | 8 | ||||
| -rw-r--r-- | docs/hazmat/primitives/symmetric-encryption.rst | 4 | ||||
| -rw-r--r-- | tests/hazmat/primitives/test_ciphers.py | 12 |
3 files changed, 23 insertions, 1 deletions
diff --git a/cryptography/hazmat/primitives/ciphers/base.py b/cryptography/hazmat/primitives/ciphers/base.py index d366e4cf..2c804cac 100644 --- a/cryptography/hazmat/primitives/ciphers/base.py +++ b/cryptography/hazmat/primitives/ciphers/base.py @@ -16,12 +16,18 @@ from __future__ import absolute_import, division, print_function from cryptography import utils from cryptography.exceptions import ( AlreadyFinalized, NotYetFinalized, AlreadyUpdated, -) + UnsupportedInterface) + +from cryptography.hazmat.backends.interfaces import CipherBackend from cryptography.hazmat.primitives import interfaces class Cipher(object): def __init__(self, algorithm, mode, backend): + if not isinstance(backend, CipherBackend): + raise UnsupportedInterface( + "Backend object does not implement CipherBackend") + if not isinstance(algorithm, interfaces.CipherAlgorithm): raise TypeError("Expected interface of interfaces.CipherAlgorithm") diff --git a/docs/hazmat/primitives/symmetric-encryption.rst b/docs/hazmat/primitives/symmetric-encryption.rst index 741091b2..71a1064e 100644 --- a/docs/hazmat/primitives/symmetric-encryption.rst +++ b/docs/hazmat/primitives/symmetric-encryption.rst @@ -56,6 +56,10 @@ an "encrypt-then-MAC" formulation as `described by Colin Percival`_. :class:`~cryptography.hazmat.backends.interfaces.CipherBackend` provider. + :raises cryptography.exceptions.UnsupportedInterface: This is raised if the + provided ``backend`` does not implement + :class:`~cryptography.hazmat.backends.interfaces.CipherBackend` + .. method:: encryptor() :return: An encrypting diff --git a/tests/hazmat/primitives/test_ciphers.py b/tests/hazmat/primitives/test_ciphers.py index d9f83535..e1f5dbc3 100644 --- a/tests/hazmat/primitives/test_ciphers.py +++ b/tests/hazmat/primitives/test_ciphers.py @@ -17,10 +17,15 @@ import binascii import pytest +from cryptography.exceptions import UnsupportedInterface + +from cryptography.hazmat.primitives import ciphers from cryptography.hazmat.primitives.ciphers.algorithms import ( AES, Camellia, TripleDES, Blowfish, ARC4, CAST5, IDEA ) +from cryptography.hazmat.primitives.ciphers.modes import ECB + class TestAES(object): @pytest.mark.parametrize(("key", "keysize"), [ @@ -120,3 +125,10 @@ class TestIDEA(object): def test_invalid_key_size(self): with pytest.raises(ValueError): IDEA(b"\x00" * 17) + + +def test_invalid_backend(): + pretend_backend = object() + + with pytest.raises(UnsupportedInterface): + ciphers.Cipher(AES(b"AAAAAAAAAAAAAAAA"), ECB, pretend_backend) |