A New Privacy-Preserving Broadcast Encryption Scheme from DPVS

In this paper, we consider the privacy-preserving problem in the context of broadcast encryption. We provide a security definition for privacy-preserving broadcast encryption, and construct a new scheme. To achieve privacy-preserving, we blind the cipher texts using the random factors. Moreover, we use a pair of orthonormal bases to construct secret key and cipher texts for proper decryption. Our privacy-preserving broadcast encryption scheme can be proven in the adaptive model without random oracle. The key technique used to obtain our result is an elaborate combination of the dual system encryption proposed by Waters and a new approach on bilinear pairings using the notion of dual pairing vector spaces (DPVS) proposed by Okamoto and Takasima.