I'm struggling to fully understand how encryption works and is coded, particularly with python. I'm just trying to get the basics down and create code in the simplest form.
I'm going to be passing a userID between two different sites, but obviously I need this to be encrypted with a private key so Website2 knows it came from Website1. This seems to be the code for me: http://docs.python.org/library/hashlib.html#module-hashlib, but it doesn't have very good examples (or maybe I'm in the wrong spot).
The problem I'm having is fully understanding how to encode and decode.
So lets say the shared private key which each website will know is:
shared_private_key = "ABCDEF"
And I want Website1 to pass to Website2 the userID of:
userID = "123456"
How would Website1 encrypt my userID with the private key in a fashion that the encryption can be sent via HTTP headers, and then have Website2 decrypt and be able to read the userID using the shared private key?
I apologize for asking such a basic question, but I'm failing to grasp how this should be done. Thanks.