Well, Windows is not my favorite OS, but still Windows and Windows Servers are very popular. I received a lot of queries on how to authenticate against SecurePass using RADIUS and I decided to write a small program in C# and share it with everybody.
The code is just an example and has been tested using Mono under Mac OS X, but should work fine under Windows with Visual Studio.
First of all, you will need the dotnet radius client library from http://code.google.com/p/dotnet-radius-client-library/. If you are running under Windows, you can download the pre-compiled DLL, otherwise you have to check-out the source files and compile them yourself.
Please have a look at the comments for more information.