区块链上多类型用户属性基可搜索加密方案

A Multi⁃type User Attribute⁃based Searchable Encryption Scheme on Blockchain

可搜索加密是在不可信云环境中实现文件密文搜索的一种密码原语。数据使用者通过检索加密关键字,来搜索云服务器中的加密文件。当前可搜索加密方案存在设计比较单一,不能有效满足使用中复杂场景实际要求,且易遭受重放攻击。本文设计一种区块链上多类型用户属性基可搜索加密方案,构建多种数据使用者模型,可以在进行多样性细粒度访问控制的同时,提高密文搜索效率。同时,针对因重放攻击带来的搜索陷门盗用问题,提出解决方案,保护数据安全以及用户隐私。经过安全性分析与实验测试证明文中方案的关键字密文与陷门在选择明文攻击下是安全的(IND-CPA安全),且满足多种数据使用者对数据的不同搜索需求。

Searchable encryption is a cryptographic primitive for encrypted files searching in untrusted cloud environment,where data users search for encrypted files in cloud server by retrieving the encrypt⁃ed keywords.Due to simple design,existing searchable encryption schemes could not satisfy the actual requirements in practical complex scenarios and are vulnerable to the replay attack.In this paper,a multi⁃type user attribute⁃based searchable encryption scheme on blockchain is designed and multiple da⁃ta user models are established,which could improve the ciphertext searching efficiency while carrying out diversity and fine⁃grained access control.Meanwhile,to address the problem of search trapdoor em⁃bezzlement caused by the replay attack,a solution is proposed to protect data security and user privacy.Security analysis and experiment tests demonstrate that with the proposed scheme,the keyword cipher⁃text and the trapdoor are secure under the selected plaintext attacks(i.e.IND⁃CPA security),satisfying various data searching demand from diverse data users.