Speaker: Zhiguo Wan, lecturer in school of software, Tsinghua University

Time: 9:00- 10:00 am, April 2, 2015

Venue: Room 202, Second Floor, Office Building, Software Campus

Host：Baoquan Chen

Topic: Achieving Verifiability for Private Multi-Keyword Search over Encrypted Cloud Data

Abstract: Cloud computing revolutionizes the traditional computation model by offering almost unlimited computation and storage resources. Such a computation model poses a challenge on data privacy and verifiability of computation. In this work we study the multi-keyword search problem over outsourced data, for which existing solutions only consider data/keyword privacy under the honest-but-curious server model. To achieve both data/keyword privacy and computation verifiability, we propose two verifiably private multi-keyword search schemes over encrypted cloud data under the stronger malicious server model. They are designed by adapting the homomorphic MAC techniques to work with a private multi-keyword search mechanism. Our first scheme VPSearch-OWF is extremely efficient for lightweight keyword search functions, while the second scheme VPSearch-CFE performs much better for computationally intensive search functions. We analyze security and features of the proposed schemes, and further discuss a probabilistic approach for top-K retrieval of search results. Then we evaluate the performance of VPSearch-CFE with an implementation based on the PBC library on an ordinary laptop, and VPSearch-OWF is expected to be much more efficient as it involves no expensive public key operations. For VPSearch-CFE our results show that the client needs only 47ms to generate authentication tags for a file with 100 keywords, and the verification is even more efficient–1024 search results can be verified with about 2 seconds.

Bio: Dr. Zhiguo Wan obtained his Ph.D. degree from School of Computing, National University of Singapore in 2007, and has been a postdoc researcher in the electronic engineering department of KULeuven in Belgium from 2006-2008. Since 2008, he has been a lecturer in school of software, Tsinghua University. His main research interests include cryptography, information security, and privacy protection. He is member of ACM, IEEE and CCF. He has been the principle investigator for 7 projects, including 3 NSFC projects. He has published over 30 papers on reputable international conferences and journals, including INFOCOM，IEEE Trans. Wireless Communications, IEEE Trans. Vehicular Networks, IEEE Trans. Information Forensics and Security, IEEE Trans. Multimedia, IEEE Trans. Industrial Electronics. He has been the local chair for WASA 2010 and BodyNets 2011, and the PC member for over 20 international conferences. He has also been the reviewer for a number of IEEE Transactions.