Question

I have heard about people starting encryption and thought it may be something I would like, so I checked XOR and can’t make any sense of it.
So can someone explain to me what XOR is ?

Answer 1

XOR is a logical operation, pronounced exclusive or. It can be used to cipher messages simply and fast. You can see a truth table for this operation here: http://mathworld.wolfram.com/XOR.html

quasi-pseudo code implementation (via http://www.evanfosmark.com/2008/06/xor-encryption-with-python/):

#!/usr/bin/env python

from itertools import izip, cycle

def xor_crypt_string(data, key):
    return ''.join(chr(ord(x) ^ ord(y)) for (x,y) in izip(data, cycle(key)))

my_data = "Hello. This is a secret message! How fun."
my_key= "firefly"

# Do the actual encryption
encrypted = xor_crypt_string(my_data, key=my_key)

print encrypted
print '---->'

# This will obtain the original data from the encrypted
original = xor_crypt_string(encrypted, key=my_key)

print original

Output:

.     BY2F
FRR
DF$IB
---->
Hello. This is a secret message! How fun.