报告题目: Online/Offline Direct CCA-2 Secure Key-Policy Attribute-Based Encryption

报告人: 伍前红 教授 （北京航空航天大学）       

主持人：张磊 副研究员

报告地点：中北校区数学馆２０１

报告时间：５月８日周五 10：00－11:30

报告人简介：

       伍前红于2004年获西安电子科技大学密码学博士学位，博士毕业后先后任澳大利亚伍伦贡大学计算机与软件工程系副研究员，武汉大学计算机学院副教授，西班牙诺维拉伊.贝尔吉尼大学计算机与数学系研究主任，目前任北京航空航天大学电子信息工程学院教授。他的研究领域主要包括公钥密码学、信息安全、车载网络安全与计算安全，主持和承担中国、澳大利亚、西班牙和欧盟项目8项，申请国家发明专利10余项，在Eurocrypt, Asiacrypt, IEEE/ACM Transactions on Networking, IEEE Transactions on Computers, IEEE Transactions on Information Forensics and Security, IEEE Transactions on Vehicular Technology等国际期刊和会议上发表论文100余篇。担任多个密码学与信息安全领域国际会议程序会员会委员，中国密码学会青年专委会理事。

报告摘要：

       This report concentrates on practical Key-Policy Attribute-Based Encryption (KP-ABE) with semantic security against adaptively chosen ciphertext attacks (CCA2) in the standard model. We propose a direct CCA2-secure KP-ABE based on a recent KP-ABE scheme that is proven to be secure against chosen-plaintext attacks (CPA) at only the cost of a Chameleon hash. Instead of extending one user hierarchy in the recent Boyen-Mei-Waters approach from CPA-secure (l+1)-Hierarchical Identity Based Encryption ((l+1)-HIBE) to CCA2-secure l-HIBE, our approach only adds one on-the-fly dummy attribute. Further, our approach only requires that the underlying ABE is selectively secure. A major obstacle for security proof in this scenario is that the simulator cannot prepare the challenge ciphertext associated with the on-the-fly dummy attribute due to the selective security constraint. We circumvent this obstacle with a Chameleon hash. Technically, unlike the previous main use of Chameleon hash in (online/offline) signature applications, our work shows Chameleon hash can also have unique applications in the constructions and the security proofs of encryption schemes.