Abstract: In order to solve the problem that the existing searchable encryption schemes cannot track the identity of the private key leaker, this paper proposes an accountable multi-keyword ciphertext search scheme. By introducing a tracking algorithm, the identity of the private key owner is tracked based on the private key that is leaked or sold,and the user is held accountable. If it is determined that the user is a leaker, it can be revoked directly from the system to ensure the security of the system. This scheme has proven to be accountable and based on[q'- SDH]assumption it is secure. At the same time, the scheme in this paper divides the encryption phase into online encryption and offline encryption, which effectively reduces the calculation amount of online encryption and improves the overall operating efficiency of the system. In addition, the scheme also supports multi-keyword query, narrowing the query scope for users, and improving search efficiency. Finally, the security proof and experimental analysis are given to prove that the scheme is safe and feasible.

Key words: searchable encryption, attribute-based encryption, accountability, multi-keyword, online/offline

摘要： 为了解决现有的可搜索加密方案无法对私钥泄露者的身份进行追踪问责等问题，提出了一种可问责的多关键字密文搜索方案。引入一个追踪算法，根据被泄露、出售的私钥追踪到私钥所有者的身份，并对该用户进行问责。如果确定该用户为泄密者，可直接将其从系统中撤销，从而保障系统的安全。经证明，该方案是可问责的并且基于[q' - SDH]假设是具有安全性的。同时，该方案将加密阶段分为离线加密和在线加密，有效地减少了在线加密的计算量，提升了系统整体运行效率。此外，该方案还支持多关键字查询，为用户缩小了查询范围，搜索效率得到了提升。最后，给出了安全性证明和实验分析，证明了该方案是安全的、可行的。

关键词: 可搜索加密, 属性基加密, 可问责, 多关键字, 在线/离线