Python / Cryptography / Blowfish — Using Blowfish and b64decode to store encrypted data

I used this just the other day, with reference from its use in Satchmo payment processing to build a unique encrypted link for our affiliate clients.

I wanted them to have an easy, one click link that they can use to visit their information instead of having to remember a password (FAILS, unless service is important enough).

I used Blowfish in the Python Cryptography Toolkit.

import bas64from Crypto.Ciphers import Blowfish

encryption_object = Blowfish.new("my-key-of-some-kind") # keep this key.. I used the django settings.SECRET_KEY
encryption_object.encrypt() 

# requires multiple of 8 character input, so we must check if our string to encrypt is a multiple of 8 and add extra characters when it's short 
padding = ''
if (len(STRING_TO_ENCRYPT) % 8  ) <> 0    :  
    padding = 'X' * (8-(len(STRING_TO_ENCRYPT) % 8))  
    # len(STRING_TO_ENCRYPT) % 8 returns the remainder of division
    # subtracting this from 8 gives you the number needed to reach the multiple of 8.

encrypted_string = base64.b64encode(encryption_object.encrypt(STIRNG_TO_ENCRYPT+padding))
# b64encode to create a "more" url-safe string.


encryption_object.decode(base64.b64decode(encrypted_string)).rstrip('X') 

Now I can encrypt something like a slug and use it as a unique link that is only available to the person who I send the link to.

Another way I’ve done that is to use a 1 way hash: store a hash on the model of the slug and look up the DB object by hash.

I just didn’t want to add a new field and deal with updating DBs to add this feature.