一对多场景下的公钥时控性可搜索加密

Public Key Timed-Release Searchable Encryption in One-to-Many Scenarios

为有效解决多接收者时间相关密文检索问题,采用广播加密技术提出一对多公钥时控性可搜索加密机制——发送者将加密的数据发送至云服务器,使得仅授权用户组成员可检索下载包含特定关键词的密文,但只能在指定的未来时间之后解密.给出方案及其安全游戏模型的形式化定义,提出两种基于q-DBDHI问题的可证明安全方案,并严格证明所提方案在自适应选择明文攻击下是安全的,效率分析表明,两种方案在执行过程中,实现了计算、存储、传输规模与用户规模无关;与相关方案相比,方案2具有更高效率.

To solve the multi-receiver time-dependent ciphertext retrieval problem efficiently, by borrowing the technique of identity-based broadcast encryption, we propose a cryptosystem of one to many public key timed-release searchable encryption （ PKTRSEOM ）. In our PKTRSEOM model, the sender transmits an encrypted message to cloud server so that only the intended authorized user group member can search the target ciphertext containing specified keywords, but cannot decrypt it until the release time in the future. We formalize the notion of PKTRSEOM and its security game model. Then, we construct two provably secure PKTRSEOM schemes which are secure under the q-DBDHI assumption and give the rigorous proof for both schemes. The efficiency analysis shows that the two schemes achieve constant costs from the sender＇ s and the recipient＇ s points of view in the running process of the system and the second scheme is more efficient than the relevant schemes.