Cygwin - Linux like environment on Windows

Cygwin is:

a collection of tools which provide a Linux look and feel environment for Windows.
a DLL (cygwin1.dll) which acts as a Linux API layer providing substantial Linux API functionality.

http://www.cygwin.com/

Crypto++ Library - C++ library

Crypto++ Library is a free C++ class library of cryptographic schemes.

http://www.cryptopp.com/