The PBC library is a free portable C library designed to make it easy to implement pairing-based cryptosystems. It provides an abstract interface to a cyclic group with a bilinear pairing, and the programmer does not need to worry about, or even know about elliptic curves.

It is built on top of GMP, another C library which performs arbitrary precision arithmetic on integers, rationals and floats with strong emphasis on portability and speed.

The PBC library homepage: http://crypto.stanford.edu/pbc/

The GMP library homepage: http://www.swox.com/gmp/