一种基于身份分层结构加密算法的广播加密方案

A Broadcast Encryption Scheme Using Hierarchical Identity-based Encryption

现今大部分的广播加密方案使用对称密钥作为用户密钥.为了解决消息发布方和用户持有相同对称密钥所带来的密钥泄漏问题,本文使用基于Weil配对性质的HIBE算法,利用子集覆盖框架下的完全子树方法构造了一种基于身份的广播加密方案.该方案使用用户的身份作为加密的公共密钥,因此无须单独的公钥/证书发布系统.同时该算法利用HIBE中的层次密钥算法,使得用户所需的私钥存储空间从O(logN)减少到O(1).本文最后对该方案的安全性、效率和动态可扩展性进行了讨论和分析.这种基于身份分层结构加密算法的广播加密方案是一种很有应用前景的适用于无状态接收装置的广播加密方案.

Nowadays most of the broadcast encryption schemes are designed to work in symmetric key setting. The message distributor and client user have to keep the same symmetric keys,which leads to the problem of key compromise. In order to get a good solution to the problem,an ID-based broadcast encryption scheme was designed using the latest HIBE algorithm based on Weil Pairings and the complete subtree method under the subset cover framework. In this scheme, the user＇s ID was used as public key for encryption. So the public key/certificates distribution system was not necessary. And the number of private keys which users have to keep reduced from O（logN） to O（1） because of the key hierarchical generation in HIBE algorithm. Finally the cryptanalysis and the discussion of efficiency and dynamic extensibility were given as well. Therefore the broadcast encryption scheme using HIBE algorithm could be widely used for stateless receivers,especially in DRM fields.