libsodium-net, or better said, libsodium for .NET, is a C# wrapper around libsodium. For those that don't know, libsodium is a portable implementation of Daniel Bernstein's fantastic NaCl library. If you aren't familiar with NaCl, I highly suggest that you look into libsodium and NaCl before using this library.NaCl is a great library in that its designed has made the right choices on what to implement and how - something most developers don't know how to do. So by using it (or a wrapper), many of those details are abstracted away where you don't need to worry about them. NaCl itself is less than portable C, only targeted for *nix systems; libsodium solves this by making it portable and making a few minor changes to better suite being distributed as a compiled binary.