A Secure and Efficient Key-Policy Attribute Based Key Encryption Scheme

Attribute based encryption has captured the attention of crypto-researchers in recent years, which can be regarded as a special type of identity based encryption integrated with flexible access control policy. In this paper, we propose a new construction of key-policy attribute based encryption, which is proved to be secure in the Selective-Set model of security under the decisional BDH assumption in the random oracle model. The proposed scheme not only provide public parameters whose size is independent of the number of attributes in each identity (used as public key), but also it has useful structures which result in more efficient key extraction and encryption than the Goyal et al.´s key-policy attribute based encryption scheme, which is proved to be secure in the Selective-Set model of security under the decisional BDH assumption in the standard model.