We provide new constructions of Leakage-Resilient IdentityBased Encryption systems (IBE) in the Standard model. We apply a hash proof technique in the existing IBE schemes of Boneh-Boyen, Waters, and Lewko-Waters. As a result, we achieve leakage-resilience under the respective static assumptions of the original systems in the Standard model. The first two systems are secure under the simple Decisional Bilinear Diffie-Hellman assumption (DBDH). The first system is selectively secure and serves as a stepping stone to construct the fully secure system. This second system is the first leakage-resilient fully secure system under DBDH in the Standard model. Finally the third system achieves full security with shorter public parameters but is based on three non-standard static assumptions. The efficiency of our transformed systems is almost the same as the original ones.
Sherman S. M. Chow, Yevgeniy Dodis, Yannis Rousela