ACAC Seminar Abstract

ACAC Seminar Abstract

ACAC Seminars

ACAC Seminar Abstract

Common Secure Index for Conjunctive Keyword-Based Retrieval over Encrypted Data

Speaker: Peishun Wang
Date, Time: Thu, 20 Sep 2007 13:00

Storages and backups of clients' data on remote untrusted servers are increasingly outsourced to data warehouses, and privacy invasion incidents about clients' sensitive data, such as information leakage caused by server administrator, have been increasing more and more. The typical way to preserve clients' privacy is to store data in the form of ciphertext. It is important to build secure indices which enable a legitimate user to search encrypted data without decrypting them and revealing any information about the data to any other. In the literature, there are a number of research works on this topic \cite{BKM05,BW06,G04,GSW04,SWP00}, but the common setting of previous works is limited to a single-user. In realistic environments, however, secret data may be shared by a group, so group setting is more practical. In this paper, we investigate common secure indices which can make multi-users in a dynamic group to obtain securely the encrypted documents shared among the group members without re-encrypting them. We give a formal definition of common secure index for conjunctive keyword-based retrieval over encrypted data (CSI-CKR), define the security requirement for CSI-CKR, and construct a CSI-CKR based on dynamic accumulators, Paillier's cryptosystem and blind signatures. The security of proposed scheme is proved under strong RSA and co-DDH assumptions.

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