Privacy-Preserving Searchable Encryption Scheme Based on Public and Private Blockchains  

作　　者：Ruizhong Du Caixia Ma Mingyue Li 

机构地区：[1]School of Cyberspace Security and Computer,and Hebei Province Key Laboratory of High Confidence Information System,Hebei University,Baoding 071002,China [2]College of Cyber Science,Nankai University,Tianjin 300350,China

出　　处：《Tsinghua Science and Technology》2023年第1期13-26,共14页清华大学学报（自然科学版（英文版）

基　　金：supported by the National Natural Science Foundation of China (No.61972073);the Key Program of Natural Science Foundation of Hebei Province of China (No.F2019201290);the Natural Science Foundation of Hebei Province of China (No.F2018201153).

摘　　要：While users enjoy the convenience of data outsourcing in the cloud,they also face the risks of data modification and private information leakage.Searchable encryption technology can perform keyword searches over encrypted data while protecting their privacy and guaranteeing the integrity of the data by verifying the search results.However,some associated problems are still encountered,such as the low efficiency of verification and uncontrollable query results.Accordingly,this paper proposes a Privacy-Preserving Searchable Encryption(PPSE)scheme based on public and private blockchains.First,we store an encrypted index in a private blockchain while outsourcing corresponding encrypted documents to a public blockchain.The encrypted documents are located through the encrypted index.This method can reduce the storage overhead on the blockchains,and improve the efficiency of transaction execution and the security of stored data.Moreover,we adopt a smart contract to introduce a secondary verification access control mechanism and restrict data users’access to the private blockchain through authorization for the purpose of guaranteeing data privacy and the correctness of access control verification.Finally,the security analysis and experimental results indicate that compared with existing schemes,the proposed scheme can not only improve the security of encrypted data but also guarantee the efficiency of the query.

关 键 词：private blockchain public blockchain access control forward privacy backward privacy 

分 类 号：TP3[自动化与计算机技术—计算机科学与技术]