As I wrote, I'm working with poly1305. One question: The _digest function will update the nonce value, so that by default one gets a nonce sequence of 0, 1, 2, .... In the code I'm working with (contributed by Nikos), this increment is done in a big-endian fashion, just like increments for CTR mode.
Is this going to be the common way to generate nonces for poly1305?
Regards, /Niels