Leakage-Resilient IND-CCA KEM from the Extractable Hash Proofs with Indistinguishability Obfuscation

摘要

Leakage-resilient cryptography requires that a crypto-system remain provably secure even if the attacker gets additional information about the internal states, which is usually the secret key in the scenario of public key encryption. In this paper, we propose a solution to achieve leakage resilience CCA for key encapsulation mechanisms firstly based on the all-but-one extractable hash proof system in the bounded leakage model, where to the best of our knowledge, previous leakage resilient public key encryption schemes are mostly based on the Cramer-Shoup's universal hash proof system and its variations. The main technique we employ is the indistinguishability obfuscation. Specifically, we use the obfuscated decryption program as the secret key to deal with the leakage. Although our schemes can tolerate a considerately good amount of leakage, the tolerated rate of leakage (defined as the ratio of leakage-amount to key size) is quite unsatisfactory because we use the whole obfuscated program as the secret key.