Joonsang Baek Ron Steinfeld Yuliang Zheng Formal Proofs for the Security of Signcryption. 80-98 2002 conf/pkc/2002 Public Key Cryptography http://link.springer.de/link/service/series/0558/bibs/2274/22740080.htm db/conf/pkc/pkc2002.html#BaekSZ02