Identity-based broadcast encryption with continuous leakage resilience

Identity-based broadcast encryption (IBBE) is an important type of broadcast encryption. In the paper, we put forward the formal definition and security model of IBBE with leakage-resilience. Furthermore, we propose an IBBE scheme with continuous leakage-resilience. The presented scheme is resilient to private key leakage. By refreshing the private key, our scheme can resist continuous private key leakage. Based on dual system encryption technique, we prove the security of the proposed scheme under subgroup decisional assumptions. We give the specific performance analysis of leakage-resilience. The relative leakage ratio can amount to 1/3.