Adaptively secure certificate-based broadcast encryption and its application to cloud storage service

Abstract

The existing public key broadcast encryption schemes are mainly constructed in identity-based cryptosystem, which bears the inherent problems of key escrow and key distribution. The certificate-based encryption mechanism can effectively address the problems in identity-based cryptosystem. Meanwhile, it simplifies the certificate revocation issue for traditional public key cryptosystem. Inspired by the idea of certificate-based encryption, we put forward the new primitive certificate-based broadcast encryption as well as its formal definition and security model. In virtue of prime order bilinear groups, we present an instantiation scheme of certificate-based broadcast encryption. To our best knowledge, the proposed scheme is the first adaptively secure scheme for certificate-based broadcast encryption in the standard model against chosen-ciphertext attack. Compared with the previous work, our scheme has advantages in the respects of computation cost as well as security properties. Furthermore, we present an application scenario of the proposed scheme for data access control in cloud storage service.