I tried asking this on stackoverflow because I thought it might be a simple coding question and didn't want to clutter up this amazing stack, but I received no responses.
CodesInChaos showed me that the proper implementation of Curve25519 for digital signatures is Ed25519 and also informed me that this implementation, the only implementation I can find, is very slow which I have now confirmed for myself.
I have essentially no experience with cryptography other than using the basic functions in that lib, so I'm afraid to touch it but would like higher performance.
To that end, how can the performance of k3d3/ed25519-java be improved? Anything specific I can get, preferably code, would be immensely helpful!