mirror of
https://github.com/Lekensteyn/lglaf.git
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38 lines
1.2 KiB
Python
38 lines
1.2 KiB
Python
import struct
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from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
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from cryptography.hazmat.backends import default_backend
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from lglaf import int_as_byte
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def key_transform(old_key):
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new_key = b''
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for x in range(32, 0, -1):
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c = old_key[x-1]
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if not isinstance(c, int):
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c = ord(c)
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new_key += int_as_byte(c - (x % 0x0C))
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return new_key
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def xor_key(key, kilo_challenge):
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# Reserve key
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key_xor = b''
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pos = 0
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challenge = struct.unpack('>I', kilo_challenge)[0]
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for i in range(8):
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k = struct.unpack('<I', key[pos:pos + 4])[0]
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key_xor += struct.pack('<I', k ^ challenge)
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pos += 4
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return key_xor
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def encrypt_kilo_challenge(encryption_key, kilo_challenge):
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plaintext = b''
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for k in range(0, 16):
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# Assemble 0x00 0x01 0x02 ... 0x1F byte-array
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plaintext += int_as_byte(k)
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encryption_key = key_transform(encryption_key)
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xored_key = xor_key(encryption_key, kilo_challenge)
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obj = Cipher(algorithms.AES(xored_key), modes.ECB(),
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backend=default_backend()).encryptor()
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return obj.update(plaintext) + obj.finalize()
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