Cryptography with Python - XOR Process


In this chapter, let us understand the XOR process along with its coding in Python.


XOR algorithm of encryption and decryption converts the plain text in the format ASCII bytes and uses XOR procedure to convert it to a specified byte. It offers the following advantages to its users −

  • Fast computation
  • No difference marked in left and right side
  • Easy to understand and analyze


You can use the following piece of code to perform XOR process −

def xor_crypt_string(data, key = 'awesomepassword', encode = False, decode = False):
   from itertools import izip, cycle
   import base64
   if decode:
      data = base64.decodestring(data)
   xored = ''.join(chr(ord(x) ^ ord(y)) for (x,y) in izip(data, cycle(key)))
   if encode:
      return base64.encodestring(xored).strip()
   return xored
secret_data = "XOR procedure"

print("The cipher text is")
print xor_crypt_string(secret_data, encode = True)
print("The plain text fetched")
print xor_crypt_string(xor_crypt_string(secret_data, encode = True), decode = True)


The code for XOR process gives you the following output −



  • The function xor_crypt_string() includes a parameter to specify mode of encode and decode and also the string value.

  • The basic functions are taken with base64 modules which follows the XOR procedure/ operation to encrypt or decrypt the plain text/ cipher text.

Note − XOR encryption is used to encrypt data and is hard to crack by brute-force method, that is by generating random encrypting keys to match with the correct cipher text.