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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.
import binascii
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,
)
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(f"\nCOUNT = {count}")
count += 1
output.append(f"KEY = {key}")
output.append(f"OFFSET = {offset}")
output.append(f"PLAINTEXT = {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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