40 lines
1.2 KiB
Python
40 lines
1.2 KiB
Python
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#!/usr/bin/env python3
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def generator(g, x, p):
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return pow(g, x) % p
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# xor encryption is symmetric, apart
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# from the reversing part
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def dynamic_xor_decrypt(plaintext, text_key):
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cipher_text = ""
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key_length = len(text_key)
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for i, char in enumerate(plaintext):
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key_char = text_key[i % key_length]
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encrypted_char = chr(ord(char) ^ ord(key_char))
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cipher_text += encrypted_char
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return ''.join(reversed(cipher_text))
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def decrypt(cipher, key):
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plaintext = ''
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for char in cipher:
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plaintext += chr(char // (key * 311))
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return plaintext
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cipher = [151146, 1158786, 1276344, 1360314, 1427490, 1377108, 1074816, 1074816, 386262, 705348, 0, 1393902, 352674, 83970, 1141992, 0, 369468, 1444284, 16794, 1041228, 403056, 453438, 100764, 100764, 285498, 100764, 436644, 856494, 537408, 822906, 436644, 117558, 201528, 285498]
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if __name__ == '__main__':
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p = 97
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g = 31
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a = 97
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b = 22
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u = generator(g, a, p)
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v = generator(g, b, p)
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key = generator(v, a, p)
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b_key = generator(u, b, p)
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assert key == b_key
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decrypted = decrypt(cipher, key)
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xor_decrypted = dynamic_xor_decrypt(decrypted, 'trudeau')
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print(xor_decrypted)
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