Jun-Bum Shin Kwangsu Lee Kyungah Shim New DSA-Verifiable Signcryption Schemes. 35-47 2002 conf/icisc/2002 ICISC http://link.springer.de/link/service/series/0558/bibs/2587/25870035.htm db/conf/icisc/icisc2002.html#ShinLS02