Currently working on an assignment for my Internet Security unit and needed an open source crypto library. Had a look at a couple I already had installed on my workstation and a couple of others including:
Polarssl looked interesting though in the end I have decided on the Botan C++ library for a couple of reasons:
Just downloaded it and built the library on Arch x86_64 with no problems. Final target machine is also x86_64 so it looks good. Not sure if I should go with a dynamic or static library. I don't have root access to the final target machine so would need to use LD_LIBRARY_PATH to allow a dynamic library to load from a non standard directory.