Test if L3 is L3 XOR {1} in the other case. H/W 1.

feistel_test.py

#!/usr/bin/env python3


import itertools
import string
from pprint import pprint
from binascii import unhexlify, hexlify

def cmp(a, b):

    xored_b = ''.join(['{:02x}'.format(b ^ 0xFF) for b in unhexlify(b)])

    if a == xored_b:
        print('{}:{} matches'.format(a, b))
        
    else:
        print('{}:{} x      '.format(a, b))

def main():
    cmp('29634d75', '8d91d162')
    cmp('25b14856', '107f0959')
    cmp('6d4e0fdc', '92b1f023')
    cmp('c3c36462', '3c3c9b9d')
    cmp('fc617adb', '260568f5')
    cmp('3a894ef6', '86d11f43')
    cmp('ddd87290', '22278d6f')
    cmp('91612be2', '6e9ed41d')
    cmp('9ef66c9f', '60692649')
    cmp('fb3549e8', 'a9a871d5')


main()

Output:

29634d75:8d91d162 x      
25b14856:107f0959 x      
6d4e0fdc:92b1f023 matches
c3c36462:3c3c9b9d matches
fc617adb:260568f5 x      
3a894ef6:86d11f43 x      
ddd87290:22278d6f matches
91612be2:6e9ed41d matches
9ef66c9f:60692649 x      
fb3549e8:a9a871d5 x      
[Finished in 0.2s]