3
votes
2answers
102 views

What is the function of the secret key “r” in Poly1305?

Poly1305-AES uses two per-connection keys $k$ (for AES) and $r$ (for Poly1305's compression function) and a per-message nonce n to execute. I've read the original paper on the implementation, and I ...
2
votes
2answers
191 views

Encrypting and MACing different data with same key

It's a well-known best practice to not use one key to both encrypt and MAC data. In my application, there are instances where I MAC a piece of data without having encrypted it first. Do I still need a ...