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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
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import ciphers
from cryptography.hazmat.primitives.ciphers import algorithms
_RFC6229_KEY_MATERIALS = [
(True,
8 * '0102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f20'),
(False,
8 * '1ada31d5cf688221c109163908ebe51debb46227c6cc8b37641910833222772a')
]
_RFC6229_OFFSETS = [
0,
16,
240,
256,
496,
512,
752,
768,
1008,
1024,
1520,
1536,
2032,
2048,
3056,
3072,
4080,
4096
]
_SIZES_TO_GENERATE = [
160
]
def _key_for_size(size, keyinfo):
msb, key = keyinfo
if msb:
return key[:size // 4]
else:
return key[-size // 4:]
def _build_vectors():
count = 0
output = []
key = None
plaintext = binascii.unhexlify(32 * '0')
for size in _SIZES_TO_GENERATE:
for keyinfo in _RFC6229_KEY_MATERIALS:
key = _key_for_size(size, keyinfo)
cipher = ciphers.Cipher(
algorithms.ARC4(binascii.unhexlify(key)),
None,
default_backend())
encryptor = cipher.encryptor()
current_offset = 0
for offset in _RFC6229_OFFSETS:
if offset % 16 != 0:
raise ValueError(
"Offset {} is not evenly divisible by 16"
.format(offset))
while current_offset < offset:
encryptor.update(plaintext)
current_offset += len(plaintext)
output.append("\nCOUNT = {}".format(count))
count += 1
output.append("KEY = {}".format(key))
output.append("OFFSET = {}".format(offset))
output.append("PLAINTEXT = {}".format(
binascii.hexlify(plaintext)))
output.append("CIPHERTEXT = {}".format(
binascii.hexlify(encryptor.update(plaintext))))
current_offset += len(plaintext)
assert not encryptor.finalize()
return "\n".join(output)
def _write_file(data, filename):
with open(filename, 'w') as f:
f.write(data)
if __name__ == '__main__':
_write_file(_build_vectors(), 'arc4.txt')
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