Chenxi Wang William A. Wulf Towards a Scalable PKI for Electronic Commerce Systems. 132-136 1999 conf/wecwis/1999 WECWIS https://doi.org/10.1109/WECWIS.1999.788201 https://doi.ieeecomputersociety.org/10.1109/WECWIS.1999.788201 db/conf/wecwis/wecwis1999.html#WangW99