Joseph K. Liu Joonsang Baek Willy Susilo Jianying Zhou Certificate-Based Signature Schemes without Pairings or Random Oracles. 285-297 2008 ISC http://dx.doi.org/10.1007/978-3-540-85886-7_20 conf/isw/2008 db/conf/isw/isc2008.html#LiuBSZ08