Pairing-based cryptography is a relatively young area of cryptography
that revolves around a certain function with special properties.

The PBC (Pairing-Based Cryptography) library is a free C library
(released under the GNU Public License) built on the GMP library that
performs the mathematical operations underlying pairing-based
cryptosystems.

The PBC library is designed to be the backbone of implementations of
pairing-based cryptosystems, thus speed and portability are important
goals. It provides routines such as elliptic curve generation, elliptic
curve arithmetic and pairing computation. Thanks to the GMP library,
despite being written in C, pairings times are reasonable.

WWW:	http://crypto.stanford.edu/pbc/