This project is meant to cover a lot of ground!
The Atmel CryptoAuth chips are quite useful for offloading the heavy lifting involved in crypto for authentication as well as checksumming and fast random number generation.
As it turns out, the AT88CK590 (primarily used for evaluating the three main chips they sell) is a handy little device in its own right. With a little solder you can extend its main functionality, learn about USB (and Python 3!) with it, and even learn about the intricacies of firmware updating.
Enjoy this project?