An efficient electronic marketplace bidding auction protocol with bid privacy

The multiagent negotiation testbed proposed by Collins was modified. It utilizes publish/subscribe system, timerelease cryptography and anonymous communication. The proposed protocol reduces DOS attack and avoids replay data attack by providing ticket token and deal sequence number to the supplier. And it is proved that generating random number to the supplier by market is better than the supplier doing it by him in guaranteeing anonymity. Market publishes an interpolating polynomial for sharing the determination process data. It avoids collusion between a customer and a certain supplier. According to the comparison and analysis with other protocols, the proposed protocol shows good security and better efficiency.      

一种高效的具有属性撤销的访问控制协议

采用外包计算技术构造一种基于密文策略的属性加密数据访问控制方法,具有高效的属性撤销功能,可以减少用户的计算量和通信量.其最大特点是将解密秘钥分为两部分,一部分发送给云服务器,另一部分发送给用户,使得云服务器可以帮助用户解密密文,减少了用户计算量,也减少了用户和云服务器的通信量.