A key-policy attribute-based broadcast encryption

According to the broadcast encryption scheme with wide applications in the real world without considering its security and efficiency in the model simultaneously an “unbounded”, Key-Policy Attribute-Based Broadcast Encryption scheme(KP-ABBE) was proposed by combining with waters dual system encryption, attribute-based encryption and broadcast encryption system. Based on the standard model, the scheme can achieve constant-size public parameters, the public parameters do not impose additional limitations on the functionality of the systems (unbounded) and either a small universe size or a bound on the size of attribute sets avoid to fixed at setup. The scheme is proved by using the dual system encryption argument and the four static assumptions which do not depend on the number of queries the attacker makes. The analysis results show that the scheme of this paper is selective secure.