维度不变的格基代理广播加密方案

摘要

To resolve the security and efficiency problems of the broadcast encryption under the quantum computing,by using the lattice basis delegation technique proposed by Agrawal,et al,this paper proposed an identity-based broadcast encryption scheme on lattice.The scheme used the structure between parents lattice and children lattice to show the relationship between the system’s master key and private key owned by authorized users.The authorized users could receive broadcast information properly by the private key.The significant difference from the past schemes was that the new one didn’t increase the dimen-sion of the user’s private key upon delegation.The scheme is adaptively secure where the security is reduced to the hardness of learning with error(LWE)problems in the random oracle model.%为解决量子环境下广播加密的安全和效率问题，结合 Agrawal 等人提出的维度不变的格基代理生成算法，设计出一种格上基于身份的广播加密方案。该方案采用父格与子格的结构关系来表示系统主私钥与合法用户私钥的对应关系，合法用户可以利用自己的私钥解密广播信息；不同于以往方案，该算法利用系统主私钥生成合法用户私钥的时候，不会增加用户私钥的维度。在随机预言机模型下证明该方案是适应性安全的，其安全性规约到错误学习（LWE）问题。