Hossein Ghodosi Josef Pieprzyk Reihaneh Safavi-Naini Huaxiong Wang On Construction of Cumulative Secret Sharing Schemes. 379-390 1998 conf/acisp/1998 ACISP http://dx.doi.org/10.1007/BFb0053749 db/conf/acisp/acisp1998.html#GhodosiPSW98