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# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import absolute_import, division, print_function
import binascii
import pretend
import pytest
import six
from cryptography.exceptions import (
AlreadyFinalized, InvalidSignature, _Reasons
)
from cryptography.hazmat.backends.interfaces import CMACBackend
from cryptography.hazmat.primitives.ciphers.algorithms import (
AES, ARC4, TripleDES
)
from cryptography.hazmat.primitives.cmac import CMAC
from ..backends.test_multibackend import DummyCMACBackend
from ...utils import (
load_nist_vectors, load_vectors_from_file, raises_unsupported_algorithm
)
vectors_aes128 = load_vectors_from_file(
"CMAC/nist-800-38b-aes128.txt", load_nist_vectors)
vectors_aes192 = load_vectors_from_file(
"CMAC/nist-800-38b-aes192.txt", load_nist_vectors)
vectors_aes256 = load_vectors_from_file(
"CMAC/nist-800-38b-aes256.txt", load_nist_vectors)
vectors_aes = vectors_aes128 + vectors_aes192 + vectors_aes256
vectors_3des = load_vectors_from_file(
"CMAC/nist-800-38b-3des.txt", load_nist_vectors)
fake_key = b"\x00" * 16
@pytest.mark.requires_backend_interface(interface=CMACBackend)
class TestCMAC(object):
@pytest.mark.supported(
only_if=lambda backend: backend.cmac_algorithm_supported(
AES(fake_key)),
skip_message="Does not support CMAC."
)
@pytest.mark.parametrize("params", vectors_aes)
def test_aes_generate(self, backend, params):
key = params["key"]
message = params["message"]
output = params["output"]
cmac = CMAC(AES(binascii.unhexlify(key)), backend)
cmac.update(binascii.unhexlify(message))
assert binascii.hexlify(cmac.finalize()) == output
@pytest.mark.supported(
only_if=lambda backend: backend.cmac_algorithm_supported(
AES(fake_key)),
skip_message="Does not support CMAC."
)
@pytest.mark.parametrize("params", vectors_aes)
def test_aes_verify(self, backend, params):
key = params["key"]
message = params["message"]
output = params["output"]
cmac = CMAC(AES(binascii.unhexlify(key)), backend)
cmac.update(binascii.unhexlify(message))
assert cmac.verify(binascii.unhexlify(output)) is None
@pytest.mark.supported(
only_if=lambda backend: backend.cmac_algorithm_supported(
TripleDES(fake_key)),
skip_message="Does not support CMAC."
)
@pytest.mark.parametrize("params", vectors_3des)
def test_3des_generate(self, backend, params):
key1 = params["key1"]
key2 = params["key2"]
key3 = params["key3"]
key = key1 + key2 + key3
message = params["message"]
output = params["output"]
cmac = CMAC(TripleDES(binascii.unhexlify(key)), backend)
cmac.update(binascii.unhexlify(message))
assert binascii.hexlify(cmac.finalize()) == output
@pytest.mark.supported(
only_if=lambda backend: backend.cmac_algorithm_supported(
TripleDES(fake_key)),
skip_message="Does not support CMAC."
)
@pytest.mark.parametrize("params", vectors_3des)
def test_3des_verify(self, backend, params):
key1 = params["key1"]
key2 = params["key2"]
key3 = params["key3"]
key = key1 + key2 + key3
message = params["message"]
output = params["output"]
cmac = CMAC(TripleDES(binascii.unhexlify(key)), backend)
cmac.update(binascii.unhexlify(message))
assert cmac.verify(binascii.unhexlify(output)) is None
@pytest.mark.supported(
only_if=lambda backend: backend.cmac_algorithm_supported(
AES(fake_key)),
skip_message="Does not support CMAC."
)
def test_invalid_verify(self, backend):
key = b"2b7e151628aed2a6abf7158809cf4f3c"
cmac = CMAC(AES(key), backend)
cmac.update(b"6bc1bee22e409f96e93d7e117393172a")
with pytest.raises(InvalidSignature):
cmac.verify(b"foobar")
@pytest.mark.supported(
only_if=lambda backend: backend.cipher_supported(
ARC4(fake_key), None),
skip_message="Does not support CMAC."
)
def test_invalid_algorithm(self, backend):
key = b"0102030405"
with pytest.raises(TypeError):
CMAC(ARC4(key), backend)
@pytest.mark.supported(
only_if=lambda backend: backend.cmac_algorithm_supported(
AES(fake_key)),
skip_message="Does not support CMAC."
)
def test_raises_after_finalize(self, backend):
key = b"2b7e151628aed2a6abf7158809cf4f3c"
cmac = CMAC(AES(key), backend)
cmac.finalize()
with pytest.raises(AlreadyFinalized):
cmac.update(b"foo")
with pytest.raises(AlreadyFinalized):
cmac.copy()
with pytest.raises(AlreadyFinalized):
cmac.finalize()
with pytest.raises(AlreadyFinalized):
cmac.verify(b"")
@pytest.mark.supported(
only_if=lambda backend: backend.cmac_algorithm_supported(
AES(fake_key)),
skip_message="Does not support CMAC."
)
def test_verify_reject_unicode(self, backend):
key = b"2b7e151628aed2a6abf7158809cf4f3c"
cmac = CMAC(AES(key), backend)
with pytest.raises(TypeError):
cmac.update(six.u(''))
with pytest.raises(TypeError):
cmac.verify(six.u(''))
@pytest.mark.supported(
only_if=lambda backend: backend.cmac_algorithm_supported(
AES(fake_key)),
skip_message="Does not support CMAC."
)
def test_copy_with_backend(self, backend):
key = b"2b7e151628aed2a6abf7158809cf4f3c"
cmac = CMAC(AES(key), backend)
cmac.update(b"6bc1bee22e409f96e93d7e117393172a")
copy_cmac = cmac.copy()
assert cmac.finalize() == copy_cmac.finalize()
def test_copy():
backend = DummyCMACBackend([AES])
copied_ctx = pretend.stub()
pretend_ctx = pretend.stub(copy=lambda: copied_ctx)
key = b"2b7e151628aed2a6abf7158809cf4f3c"
cmac = CMAC(AES(key), backend=backend, ctx=pretend_ctx)
assert cmac._backend is backend
assert cmac.copy()._backend is backend
def test_invalid_backend():
key = b"2b7e151628aed2a6abf7158809cf4f3c"
pretend_backend = object()
with raises_unsupported_algorithm(_Reasons.BACKEND_MISSING_INTERFACE):
CMAC(AES(key), pretend_backend)
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