roundfunction.py

BLOCK_LEN = 8
HEX_BLOCK_LEN = 16
def encrypt_block(plaintext):
    '''Encrypts a given block of plaintext'''
    k = open("./key").read().rstrip()
    result = int(binascii.hexlify(plaintext), 16)
    for i in range(ROUNDS):
        # The round function is the below lines
        key = int(binascii.hexlify(k[i * BLOCK_LEN:(i + 1) * BLOCK_LEN]), 16) # Grabs a block of the key
        key_odd = key | 1 # Creates an odd version of the key
        result ^= key # Xor's the result with the key
        result = g(result) # Reverses the bits in result
        result = (result * key_odd) % (1 << 64) # Multiplies the result with the odd-ed key, forces a 64-bit number
    return hex(result).lstrip("0x").rstrip("L").rjust(HEX_BLOCK_LEN, "0") # Converts the result to a 16-character hex block