基于区块链的多关键词模糊搜索加密方案

Multi-keyword Fuzzy Search Encryption Scheme Based on Blockchain

针对1对多数据密文共享中多关键词模糊匹配和用户公平性问题,该文提出一种基于区块链的多关键词模糊搜索加密方案。该文提出一种R-HashMap索引结构,通过使用对偶编码函数和位置敏感哈希函数来构建安全索引,并采用K最近邻算法来加密索引,通过计算欧式距离度量查询关键词向量与索引节点之间的相似性,实现多关键词模糊密文搜索。该文除了消除预定义词典和降低存储开销外,还在不增加搜索复杂度的前提下实现对安全索引的更新。此外,将以太坊区块链技术与可搜索加密方案相结合避免了恶意服务器对数据的篡改,使用智能合约作为可信第三方进行检索工作,不仅可以防止云服务器内部的关键词猜测攻击,还可以解决检索结果不正确的问题。通过安全性证明分析,该文不但满足自适应选择关键词语义安全性,还可以保护用户隐私和数据安全。将该文与其他方案进行实验对比,证明该文在保证精确度的前提下,时间开销上具有更好的效率优势。

Considering the problem of multi-keyword fuzzy matching and user fairness in one-to-many data ciphertext sharing,a multi-keyword fuzzy search encryption scheme based on blockchain is proposed.An R-HashMap index structure is proposed.The secure index is constructed by using pairs coding function and position sensitive hash function,and the K-nearest neighbor algorithm is used to encrypt the index.The similarity between the query keyword vector and the index node is calculated by Euclidian distance measure,and the multi-keyword fuzzy ciphertext search is realized.In addition to eliminating the pre-defined dictionary and reducing the storage overhead,this scheme also realizes the update of the security index without increasing the search complexity.In addition,the combination of Ethereum blockchain technology and searchable encryption scheme avoids data tampering by malicious servers,and the use of smart contracts as trusted third parties for retrieval work can not only prevent keyword guessing attacks within cloud servers,but also solve the problem of incorrect retrieval results.Through security proof analysis,the proposed scheme not only satisfies the semantic security of adaptive keyword selection,but also can protect user privacy and data security.The experimental comparison between this program and other schemes proves that the program has better efficiency in terms of time and cost while ensuring accuracy.