Leakage Resilient IBE and IPE schemes

We construct identity-based encryption (IBE) and inner product encryption (IPE) schemes under the decision linear (DLIN) or symmetric external Diffie-Hellman (SXDH) assumptions. Their private user keys are leakage-resilient in several scenarios. In particular, • In the bounded memory leakage model (Akavia et al., TCC ’09), our basic schemes reach the maximum-possible leakage rate 1− o(1). • In the continual memory leakage model (Brakerski et al., Dodis et al., FOCS ’10), variants of the above schemes enjoy leakage rate at least 1 2 − o(1). Among the results, we improve upon the work of Brakerski et al. by presenting adaptively secure IBE schemes.