ip.py

import random
from sbox import FakeBinary


class IP:
    def __init__(self):
        self.ip = [
        58,50,42,34,26,18,10,2,
        60,52,44,36,28,20,12,4,
        62,54,46,38,30,22,14,6,
        64,56,48,40,32,24,16,8,
        57,49,41,33,25,17,9,1,
        59,51,43,35,27,19,11,3,
        61,53,45,37,29,21,13,5,
        63,55,47,39,31,23,15,7
        ]

        self.ip1 = [
        40,8,48,16,56,24,64,32,
        39,7,47,15,55,23,63,31,
        38,6,46,14,54,22,62,30,
        37,5,45,13,53,21,61,29,
        36,4,44,12,52,20,60,28,
        35,3,43,11,51,19,59,27,
        34,2,42,10,50,18,58,26,
        33,1,41,9,49,17,57,25
        ]

    def genip(self, value, invert=False):
        def genip(value):
            for pos in (self.ip1 if invert else self.ip):
                yield str(value)[pos - 1]
        return ''.join(genip(value))

if __name__ == '__main__':
    myip = IP()
    for i in range(15):
        print "Proof %d\\\\" % (i + 1)
        # Random integer, possible to diaplay with 64 bits
        number = random.randrange(0, 18446744073709551616L, 1)
        inverse = myip.genip(FakeBinary(number, 64))
        print "$x \t\t= %s$\\\\" % (FakeBinary(number, 64))
        print "$IP(x) \t\t= %s$\\\\" % (inverse)
        params = (myip.genip(FakeBinary(inverse, 64), invert=True))
        print "$IP^{-1}(IP(x)) \t= %s$\\\\" % params
        print "\\\\"

sbox.py

class FakeBinary:
    def __init__(self, value, padding=6):
        self.padding = padding

        if type(value) == str:
            self.from_string(value)
        else:
            self.from_int(value)

    def from_int(self, value):
        self.value = value

    def from_string(self, value):
        if len(value) != self.padding:
            raise ValueError('Input must be 6 bits!')

        self.value = 0

        for i in range(len(value)):
            self.value += 2 ** i * int(value[len(value) - i - 1])

    def __unicode__(self):
        bstring = bin(self.value)[2:]
        return (self.padding - len(bstring)) * '0' + bstring

    def __str__(self):
        return unicode(self).encode('utf-8')

    def __int__(self):
        return self.value