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tobiasvl/decrypt_nsf.py

Created September 16, 2015 08:23
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decrypt_nsf.py
def decrypt(row, cipher):
plain = ""
seed = ((row * 0x1E2F) + 0xFE64) & 0xFFFFFFFF
for byte in bytes.fromhex(cipher):
mask = (seed >> 8) & 0xFF
plain += chr(byte ^ mask)
seed = (((seed + byte) * 0x0E6C9AA0) + 0x196AAA91) & 0xFFFFFFFF
plain = re.sub("[^0-9]", "", plain)
return plain
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