Ron Steinfeld Laurence Bull Huaxiong Wang Josef Pieprzyk Universal Designated-Verifier Signatures. 523-542 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=2894&spage=523 2003 conf/asiacrypt/2003 ASIACRYPT db/conf/asiacrypt/asiacrypt2003.html#SteinfeldBWP03