diff options
Diffstat (limited to 'lib/Crypto/SelfTest/Cipher/common.py')
| -rw-r--r-- | lib/Crypto/SelfTest/Cipher/common.py | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/lib/Crypto/SelfTest/Cipher/common.py b/lib/Crypto/SelfTest/Cipher/common.py index 26fabed..eacc2b5 100644 --- a/lib/Crypto/SelfTest/Cipher/common.py +++ b/lib/Crypto/SelfTest/Cipher/common.py @@ -29,7 +29,10 @@ __revision__ = "$Id$" import sys import unittest from binascii import a2b_hex, b2a_hex +if sys.version_info[0] == 2 and sys.version_info[1] == 1: + from Crypto.Util.py21compat import * from Crypto.Util.py3compat import * +from Crypto.Util.strxor import strxor # For compatibility with Python 2.1 and Python 2.2 if sys.hexversion < 0x02030000: @@ -289,6 +292,149 @@ class IVLengthTest(unittest.TestCase): def _dummy_counter(self): return "\0" * self.module.block_size +class IVAttributeTest(unittest.TestCase): + def __init__(self, module, params): + unittest.TestCase.__init__(self) + self.module = module + self.key = b(params['key']) + + def shortDescription(self): + return "Check that the IV attribute is updated after encryption and decryption" + + def runTest(self): + self._run_tests_on_module(low_level=True) + self._run_tests_on_module(low_level=False) + + def _run_tests_on_module(self, low_level): + from Crypto import Random + k = a2b_hex(self.key) + iv = Random.get_random_bytes(self.module.block_size) + zero = b("\0")*self.module.block_size + plaintext = Random.get_random_bytes(self.module.block_size) + + ## + ## ECB mode + ## + + # ECB mode doesn't have an IV, but only test the high-level API, since + # the low-level code currently behaves differently. + if not low_level: + cipher = self.module.new(k, self.module.MODE_ECB) + self.assertRaises(AttributeError, getattr, cipher, 'IV') + self.assertRaises(AttributeError, setattr, cipher, 'IV', iv) + + ## + ## CBC mode + ## + + # .IV should initially be the real IV + cipher = self.module.new(k, self.module.MODE_CBC, iv) + if low_level: + cipher = cipher._cipher + self.assertEqual(b2a_hex(iv), b2a_hex(cipher.IV)) + + # After encryption, the IV should equal the previous ciphertext block + ciphertext = cipher.encrypt(plaintext) + self.assertEqual(b2a_hex(ciphertext), b2a_hex(cipher.IV)) + + # Modifying the IV should affect encryption + cipher.IV = iv + ciphertext2 = cipher.encrypt(plaintext) + self.assertEqual(b2a_hex(ciphertext), b2a_hex(ciphertext2)) + + # Modifying the IV should affect decryption + cipher = self.module.new(k, self.module.MODE_CBC, zero) + if low_level: + cipher = cipher._cipher + cipher.IV = iv + plaintext2 = cipher.decrypt(ciphertext) + self.assertEqual(b2a_hex(plaintext), b2a_hex(plaintext2)) + + # After decryption, the IV should equal the previous ciphetext block + self.assertEqual(b2a_hex(ciphertext), b2a_hex(cipher.IV)) + + ## + ## CFB mode + ## + + # .IV should initially be the real IV + cipher = self.module.new(k, self.module.MODE_CFB, iv) + if low_level: + cipher = cipher._cipher + self.assertEqual(b2a_hex(iv), b2a_hex(cipher.IV)) + + # After encryption, the IV should equal the previous ciphertext block + ciphertext = cipher.encrypt(plaintext) + self.assertEqual(b2a_hex(ciphertext), b2a_hex(cipher.IV)) + + # Modifying the IV should affect encryption + cipher.IV = iv + ciphertext2 = cipher.encrypt(plaintext) + self.assertEqual(b2a_hex(ciphertext), b2a_hex(ciphertext2)) + + # Modifying the IV should affect decryption + cipher = self.module.new(k, self.module.MODE_CFB, zero) + if low_level: + cipher = cipher._cipher + cipher.IV = iv + plaintext2 = cipher.decrypt(ciphertext) + self.assertEqual(b2a_hex(plaintext), b2a_hex(plaintext2)) + + # After decryption, the IV should equal the previous ciphetext block + self.assertEqual(b2a_hex(ciphertext), b2a_hex(cipher.IV)) + + ## + ## OFB mode + ## + + # .IV should initially be the real IV + cipher = self.module.new(k, self.module.MODE_OFB, iv) + if low_level: + cipher = cipher._cipher + self.assertEqual(b2a_hex(iv), b2a_hex(cipher.IV)) + + # After encryption, the IV should equal the previous ciphertext block XOR the previous plaintext block + ciphertext = cipher.encrypt(plaintext) + self.assertEqual(b2a_hex(strxor(ciphertext, plaintext)), b2a_hex(cipher.IV)) + + # Modifying the IV should affect encryption + cipher.IV = iv + ciphertext2 = cipher.encrypt(plaintext) + self.assertEqual(b2a_hex(ciphertext), b2a_hex(ciphertext2)) + + # Modifying the IV should affect decryption + cipher = self.module.new(k, self.module.MODE_OFB, zero) + if low_level: + cipher = cipher._cipher + cipher.IV = iv + plaintext2 = cipher.decrypt(ciphertext) + self.assertEqual(b2a_hex(plaintext), b2a_hex(plaintext2)) + + # After decryption, the IV should equal the previous ciphetext block + self.assertEqual(b2a_hex(strxor(ciphertext, plaintext2)), b2a_hex(cipher.IV)) + + ## + ## CTR mode + ## + + # The CTR-mode nonce is accessible via the counter object, not the + # cipher itself. + if not low_level: + cipher = self.module.new(k, self.module.MODE_CTR, counter=lambda: "\0"*16) + self.assertRaises(AttributeError, getattr, cipher, 'IV') + self.assertRaises(AttributeError, setattr, cipher, 'IV', iv) + + ## + ## OPENPGP mode + ## + + # There is no low-level MODE_OPENPGP + if not low_level: + # OPENPGP mode doesn't allow you to set the IV. + cipher = self.module.new(k, self.module.MODE_OPENPGP, iv) + self.assertEqual(b2a_hex(iv), b2a_hex(cipher.IV)) + self.assertRaises(AttributeError, setattr, cipher, 'IV', zero) + def make_block_tests(module, module_name, test_data, additional_params=dict()): tests = [] extra_tests_added = 0 @@ -337,6 +483,7 @@ def make_block_tests(module, module_name, test_data, additional_params=dict()): RoundtripTest(module, params), PGPTest(module, params), IVLengthTest(module, params), + IVAttributeTest(module, params), ] extra_tests_added = 1 |