The PBC_sig signatures library contains signatures schemes that depend on a bilinear map (aka pairing), though in future conventional signature schemes may be added. PBC_sig is a free C library (released under the GNU Public License), and built upon the PBC pairing-based cryptography library.
Schemes implemented include:
Boneh-Boyen short signatures
Boneh-Boyen-Shacham short group signatures
Boneh-Lynn-Shacham short signatures
Cha-Cheon identity-based signatures
Ben Lynn wrote the original code. Hovav Shacham considerably optimized BBS group signatures. Joe Cooley contributed the autotools configuration files. David Jao upgraded the library for pbc-0.5.