Simple python XOR encrypt/decrypt

xor.py

#
# NB : this is not secure
# from http://code.activestate.com/recipes/266586-simple-xor-keyword-encryption/
# added base64 encoding for simple querystring :)
#

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 = "239054"
print xor_crypt_string(secret_data, encode=True)
print xor_crypt_string(xor_crypt_string(secret_data, encode=True), decode=True)

# NB : this is not secure

That's not entirely accurate, if key is cycled several times it's indeed trivial to break with frequency analysis. But with a key as long as what you want en encrypt, it doesn't get more secure that that. Therefore it may be a perfect fit for particular use cases (mine: I have to encrypt third party API keys, fixed length, one cipher key generated per API key.