I'm using the Crypto++ implementation of Salsa20 for a software project we are working on and I'd like to know if there are any SSE or software optimizations that will increase the speed of the CSPNG?
Looking at the Crypto++ 5.6.2 implementation for Salsa20 it seems they do have an SSE implementation, but it doesn't use intrinsics so it doesn't look very portable between compilers.
If you're not exactly set on using Salsa20 I would recommend using ChaCha20, which is a small modification of Salsa20 by the author (Daniel Bernstein) that is slightly faster and cleaner. And if you really value speed I would recommend using Salsa12, which reduces computation time by about 40%.
For ChaCha20 I would recommend the
crypto_stream\chacha20\krovetz implementation found in SUPERCOP. Similarly for ChaCha12.