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# Copyright (c) 2015, Legrandin <helderijs@gmail.com>
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import unittest
from binascii import unhexlify

from Crypto.SelfTest.st_common import list_test_cases
from Crypto.Util.py3compat import tobytes
from Crypto.Cipher import AES, DES3, DES
from Crypto.Hash import SHAKE128

def get_tag_random(tag, length):
    return SHAKE128.new(data=tobytes(tag)).read(length)

from Crypto.SelfTest.Cipher.test_CBC import BlockChainingTests

class OfbTests(BlockChainingTests):

    aes_mode = AES.MODE_OFB
    des3_mode = DES3.MODE_OFB

    # Redefine test_unaligned_data_128/64

    def test_unaligned_data_128(self):
        plaintexts = [ b"7777777" ] * 100

        cipher = AES.new(self.key_128, AES.MODE_CFB, self.iv_128, segment_size=8)
        ciphertexts = [ cipher.encrypt(x) for x in plaintexts ]
        cipher = AES.new(self.key_128, AES.MODE_CFB, self.iv_128, segment_size=8)
        self.assertEqual(b"".join(ciphertexts), cipher.encrypt(b"".join(plaintexts)))

        cipher = AES.new(self.key_128, AES.MODE_CFB, self.iv_128, segment_size=128)
        ciphertexts = [ cipher.encrypt(x) for x in plaintexts ]
        cipher = AES.new(self.key_128, AES.MODE_CFB, self.iv_128, segment_size=128)
        self.assertEqual(b"".join(ciphertexts), cipher.encrypt(b"".join(plaintexts)))

    def test_unaligned_data_64(self):
        plaintexts = [ b"7777777" ] * 100
        cipher = DES3.new(self.key_192, DES3.MODE_CFB, self.iv_64, segment_size=8)
        ciphertexts = [ cipher.encrypt(x) for x in plaintexts ]
        cipher = DES3.new(self.key_192, DES3.MODE_CFB, self.iv_64, segment_size=8)
        self.assertEqual(b"".join(ciphertexts), cipher.encrypt(b"".join(plaintexts)))

        cipher = DES3.new(self.key_192, DES3.MODE_CFB, self.iv_64, segment_size=64)
        ciphertexts = [ cipher.encrypt(x) for x in plaintexts ]
        cipher = DES3.new(self.key_192, DES3.MODE_CFB, self.iv_64, segment_size=64)
        self.assertEqual(b"".join(ciphertexts), cipher.encrypt(b"".join(plaintexts)))


from Crypto.SelfTest.Cipher.test_CBC import NistBlockChainingVectors

class NistOfbVectors(NistBlockChainingVectors):
    aes_mode = AES.MODE_OFB
    des_mode = DES.MODE_OFB
    des3_mode = DES3.MODE_OFB


# Create one test method per file
nist_aes_kat_mmt_files = (
    # KAT
    "OFBGFSbox128.rsp",
    "OFBGFSbox192.rsp",
    "OFBGFSbox256.rsp",
    "OFBKeySbox128.rsp",
    "OFBKeySbox192.rsp",
    "OFBKeySbox256.rsp",
    "OFBVarKey128.rsp",
    "OFBVarKey192.rsp",
    "OFBVarKey256.rsp",
    "OFBVarTxt128.rsp",
    "OFBVarTxt192.rsp",
    "OFBVarTxt256.rsp",
    # MMT
    "OFBMMT128.rsp",
    "OFBMMT192.rsp",
    "OFBMMT256.rsp",
    )
nist_aes_mct_files = (
    "OFBMCT128.rsp",
    "OFBMCT192.rsp",
    "OFBMCT256.rsp",
    )

for file_name in nist_aes_kat_mmt_files:
    def new_func(self, file_name=file_name):
        self._do_kat_aes_test(file_name)
    setattr(NistOfbVectors, "test_AES_" + file_name, new_func)

for file_name in nist_aes_mct_files:
    def new_func(self, file_name=file_name):
        self._do_mct_aes_test(file_name)
    setattr(NistOfbVectors, "test_AES_" + file_name, new_func)
del file_name, new_func

nist_tdes_files = (
    "TOFBMMT2.rsp",    # 2TDES
    "TOFBMMT3.rsp",    # 3TDES
    "TOFBinvperm.rsp", # Single DES
    "TOFBpermop.rsp",
    "TOFBsubtab.rsp",
    "TOFBvarkey.rsp",
    "TOFBvartext.rsp",
    )

for file_name in nist_tdes_files:
    def new_func(self, file_name=file_name):
        self._do_tdes_test(file_name)
    setattr(NistOfbVectors, "test_TDES_" + file_name, new_func)

# END OF NIST OFB TEST VECTORS


class SP800TestVectors(unittest.TestCase):
    """Class exercising the OFB test vectors found in Section F.4
    of NIST SP 800-3A"""

    def test_aes_128(self):
        plaintext =     '6bc1bee22e409f96e93d7e117393172a' +\
                        'ae2d8a571e03ac9c9eb76fac45af8e51' +\
                        '30c81c46a35ce411e5fbc1191a0a52ef' +\
                        'f69f2445df4f9b17ad2b417be66c3710'
        ciphertext =    '3b3fd92eb72dad20333449f8e83cfb4a' +\
                        '7789508d16918f03f53c52dac54ed825' +\
                        '9740051e9c5fecf64344f7a82260edcc' +\
                        '304c6528f659c77866a510d9c1d6ae5e'
        key =           '2b7e151628aed2a6abf7158809cf4f3c'
        iv =            '000102030405060708090a0b0c0d0e0f'

        key = unhexlify(key)
        iv = unhexlify(iv)
        plaintext = unhexlify(plaintext)
        ciphertext = unhexlify(ciphertext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext), ciphertext)
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext), plaintext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext[:-8]), ciphertext[:-8])
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext[:-8]), plaintext[:-8])

    def test_aes_192(self):
        plaintext =     '6bc1bee22e409f96e93d7e117393172a' +\
                        'ae2d8a571e03ac9c9eb76fac45af8e51' +\
                        '30c81c46a35ce411e5fbc1191a0a52ef' +\
                        'f69f2445df4f9b17ad2b417be66c3710'
        ciphertext =    'cdc80d6fddf18cab34c25909c99a4174' +\
                        'fcc28b8d4c63837c09e81700c1100401' +\
                        '8d9a9aeac0f6596f559c6d4daf59a5f2' +\
                        '6d9f200857ca6c3e9cac524bd9acc92a'
        key =           '8e73b0f7da0e6452c810f32b809079e562f8ead2522c6b7b'
        iv =            '000102030405060708090a0b0c0d0e0f'

        key = unhexlify(key)
        iv = unhexlify(iv)
        plaintext = unhexlify(plaintext)
        ciphertext = unhexlify(ciphertext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext), ciphertext)
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext), plaintext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext[:-8]), ciphertext[:-8])
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext[:-8]), plaintext[:-8])

    def test_aes_256(self):
        plaintext =     '6bc1bee22e409f96e93d7e117393172a' +\
                        'ae2d8a571e03ac9c9eb76fac45af8e51' +\
                        '30c81c46a35ce411e5fbc1191a0a52ef' +\
                        'f69f2445df4f9b17ad2b417be66c3710'
        ciphertext =    'dc7e84bfda79164b7ecd8486985d3860' +\
                        '4febdc6740d20b3ac88f6ad82a4fb08d' +\
                        '71ab47a086e86eedf39d1c5bba97c408' +\
                        '0126141d67f37be8538f5a8be740e484'
        key =           '603deb1015ca71be2b73aef0857d77811f352c073b6108d72d9810a30914dff4'
        iv =            '000102030405060708090a0b0c0d0e0f'

        key = unhexlify(key)
        iv = unhexlify(iv)
        plaintext = unhexlify(plaintext)
        ciphertext = unhexlify(ciphertext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext), ciphertext)
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext), plaintext)

        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.encrypt(plaintext[:-8]), ciphertext[:-8])
        cipher = AES.new(key, AES.MODE_OFB, iv)
        self.assertEqual(cipher.decrypt(ciphertext[:-8]), plaintext[:-8])


def get_tests(config={}):
    tests = []
    tests += list_test_cases(OfbTests)
    if config.get('slow_tests'):
        tests += list_test_cases(NistOfbVectors)
    tests += list_test_cases(SP800TestVectors)
    return tests


if __name__ == '__main__':
    suite = lambda: unittest.TestSuite(get_tests())
    unittest.main(defaultTest='suite')