This is my latest SilkroadSecurity API in .net 4.0 (C#). The security API supports both client and server security processing so it can be used for anything. Since it is native C# and does not use any C++ or unmanaged/unsafe code, it is x86 and x64 compatible. You can use the API through a precompiled DLL or just included the source files directly into your project.
Also included are two simple programs showing the basics of using the API. They are just quick unoptimized examples to show the API use. I would not really recommend following them as examples of how you should setup code in C# (i.e. the proxy example is a really bad design, but it works).
The API itself is designed to require as little work as possible from users. You simply feed it network data then check to see if there are any packets available for processing. For sending, you pass it your packets using the provided classes then get the finished data buffers to send. Everything in between is handled internally.
Please read the included "readme.txt" for more information on getting started with it. A good solid understanding of C# is required to make use of this! I have done pretty extensive testing with it so I'm pretty confident it's usable, but it might still have a few small bugs here or there as with anything. If you come across anything performing unexpectedly, please report it and I'll take a look.
I will post some more programs using this later after I complete them. I don't have any more details on that for now though.