Modern Python Standard Library Cookbook

How it works...

Our purpose is to ensure that any given message can't be changed in any way or it will invalidate the signature attached to the message.

So the compute_signature function, given a message and a private secret key, returns all the data that the signed message should include when it's sent to the receiver. The sent data includes the message itself, the signature, and a timestamp. The timestamp is included because, in many cases, it's a good idea to ensure that the message is a recent one. If you are receiving an API request signed with HMAC or a cookie that you just set, you might want to ensure that you are handling a recent message and not one that was sent an hour ago. The timestamp can't be tampered with as it's included ...