OpenSSL.NET - INSTALL Both libeay32.dll and ssleay32.dll are native C DLLs and as such depend on the MSVC 2010 CRT. This means you must install the Microsoft Visual C++ 2010 Redistributable Package (x86) on each machine that you wish to use OpenSSL.NET. Alternatively, you can build your own version of libeay32.dll and ssleay32.dll from source to meet whatever requirements are necessary in your environment. For development, I build these DLLs with debugging symbols so that I can step into them as needed. One could also statically link the CRT so that the MSVC 2008 CRT is not required to be installed on the target machine. Make sure you have libeay32.dll and ssleay32.dll in the current working directory of your application or in your PATH. In your .NET project, add a reference to the ManagedOpenSsl.dll assembly. If you're having trouble with the native library being loaded under mono, try using MONO_LOG_LEVEL=debug when invoking mono.