Leakage-Resilient Chosen-Ciphertext Secure Public-Key Encryption from Hash Proof System and One-Time Lossy Filter

We present a new generic construction of a public-key encryption (PKE) scheme secure against leakage-resilient chosen-ciphertext attacks (LR-CCA), from any Hash Proof System (HPS) and any one-time lossy filter (OT-LF). Efficient constructions of HPSs and OT-LFs from the DDH and DCR assumptions suggest that our construction is a practical approach to LR-CCA security. Most of practical PKEs with LR-CCA security, like variants of Cramer-Shoup scheme, rooted from Hash Proof Systems, but with leakage rates at most 1/4 − o(1) (defined as the ratio of leakage amount to secret-key size). The instantiations of our construction from the DDH and DCR assumptions result in LR-CCA secure PKEs with leakage rate of 1/2 − o(1). On the other hand, our construction also creates a new approach for constructing IND-CCA secure (leakage-free) PKE schemes, which may be of independent interest.