When redirecting we randomly generate a token for the client to use to validate on the next server. Previously this was using our existing Rand functionality that uses PCG32. While that generator is very cool and fast for games, it's not really cryptographically secure. So we want to use something better for things like tokens and password hashing.
This is pretty easy to implement, we can just wrap the system cryptographic random functions to make them available in our custom language NLL. In C++ on linux we use getrandom and in C#, System.Security.Cryptography.RandomNumberGenerator.
Currently we just generate Uint32 and Uint64 on demand, we'll probably need to extend that in the future, but it's good enough for now.