Jan Camenisch Abhi Shelat Dieter Sommer Simone Fischer-Hübner Marit Hansen Henry Krasemann Gérard Lacoste Ronald Leenes Jimmy C. Tseng 20-27 2005 conf/dim/2005 Digital Identity Management http://doi.acm.org/10.1145/1102486.1102491 db/conf/dim/dim2005.html#CamenischSSFHKLLT05