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from c2 import fixed_xor
from collections import Counter
import string
alphabet = string.ascii_lowercase + string.ascii_uppercase
def score(bs):
chars = [b for b in bs if b in alphabet]
return sum(Counter(chars).values())
def decode_cipher(x):
x = bytearray.fromhex(x)
num_bytes = len(x)
mx, result, key = 0, None, None
for c in alphabet:
mask = bytearray(bytes(c, 'ascii') * num_bytes)
y = fixed_xor(x, mask, decode_hex=False, encode_hex=False).decode('ascii')
test = score(y)
if test > mx:
result = y
mx = test
key = mask.decode('ascii')
return result
run_tests = False
if run_tests:
print(decode_cipher("1b37373331363f78151b7f2b783431333d78397828372d363c78373e783a393b3736"))
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