Mihir Bellare Daniele Micciancio Bogdan Warinschi Foundations of Group Signatures: Formal Definitions, Simplified Requirements, and a Construction Based on General Assumptions. 614-629 2003 conf/eurocrypt/2003 EUROCRYPT http://dx.doi.org/10.1007/3-540-39200-9_38 db/conf/eurocrypt/eurocrypt2003.html#BellareMW03