Xor

#Python 3.0 -- 3.4
#Save this file as .py
#Better putting this in the same directory as other files
#Files needs to be written with extension
#mgostIH
wr=""
key = 11
for i in open(input("Write file to encrypt/decrypt: "),"rb").read():
    wr+=chr(i^key)
open(input("Write output file: "),"w").write(wr)