区块链上支持多关键字检索的可搜索加密方案

在基于云存储的单关键字可搜索加密中，云服务器不是完全可信的，且现有的单关键字检索不能精确地返回搜索结果。基于此， 结合区块链技术提出了区块链上的多关键字可搜索加密方案。该方案采用对称加密算法提高了加密效率；利用区块链技术解决了云服务器不诚实搜索的问题；采用多关键字的索引结构提高了搜索结果的精确性。在随机预言模型下，证明了该方案在选择关键字攻击下是不可区分IND CKA安全的，通过效率分析表明该方案具有更高的效率。

A searchable encryption scheme supportingmulti-keyword retrieval on blockchain

In cloud based single keyword searchable encryption schemes, cloud servers are not completely trusted, and the existing single keyword retrieval cannot accurately return search results. Therefore, a multi keyword searchable encryption scheme is constructed by using blockchain technology. Our scheme uses the symmetrical encryption algorithm to improve the encryption efficiency, takes advantage of blockchain technology to solve the problem of dishonest search in cloud server, and also improves the accuracy of search results based on multi keyword index structure. The scheme is proved secure against indistinguishably chosen keyword attack (IND CKA) under the random oracle model. Furthermore, the performance analysis shows that our proposals are secure and efficient.