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    一种基于SRE的对称可搜索加密方案

    A Searchable Symmetric Encryption Scheme Based on SRE

    • 摘要: 具有前向隐私和后向隐私的动态对称可搜索加密(dynamic searchable symmetric encryption, DSSE)方案能够支持动态添加和删除密文索引且具有较高的搜索效率,一直是近年来研究的热点. 针对Aura方案中存在密文存储开销大和误删除的问题,给出了对称可撤消加密(symmetric revokable encryption,SRE)原语更严格的正确性定义,从理论上分析了误删除发生的条件,通过设计穿刺密钥位置选择算法,避免了哈希碰撞导致的节点位置重用. 在此基础上,构造了基于SRE对称可搜索加密方案. 方案利用多点可穿刺伪随机函数实现一次穿刺所有未使用节点,既有效降低了搜索时服务器的计算开销,又可避免提前暴露未使用密钥,提高方案的安全性. 最后,从搜索效率、存储开销、通信开销和安全性等方面对方案进行了分析. 理论分析和实验结果表明,所提方案不仅能够减小服务器密文存储时的空间开销,避免误删除索引,而且在大规模节点下具有更高的搜索效率.

       

      Abstract: DSSE (dynamic searchable symmetric encryption), which has forward/backward privacy and high search efficiency, supports addition and deletion of encrypted index. Relevant research has been a hot spot and many new schemes have been constructed in recent years, such as Aura. Aiming at the problems of high ciphertext storage overhead and mistaken deletion in Aura scheme, a more strict correctness definition of SRE (symmetric revokable encryption) primitive is given, and the condition of mistaken deletion is analyzed theoretically. In addition, an insertion position selection algorithm is designed to avoid node reuse due to Hash collision. On this basis, a searchable symmetric encryption scheme based on SRE is constructed by adding a deletion list and using a t-puncturable pseudorandom function. Puncturing all unused nodes at one time, the scheme not only effectively reduces the computing overhead on the cloud server during search phase, but also avoids revealing unused keys and gains better security. Finally, the scheme is analyzed in terms of search efficiency, storage overhead, communication overhead and security. Theoretical analysis and experimental results show that the scheme can effectively reduce the space overhead of ciphertext storage on the server, avoid the mistaken deletion, and improve the search efficiency on large-scale nodes.

       

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