Public-key encryption scheme with optimal continuous leakage resilience

In real-world applications, adversaries can launch leakage attacks, such as side-channel attacks, to obtain some information of the secret states (e.g. secret key, random value, etc.) in cryptographic protocols, compromising their security. Moreover, adversaries can obtain more leakage information by performing leakage attacks continuously, and the leakage attacks can be performed at any time by the adversary. Therefore, when designing public-key encryption (PKE) schemes, one should consider the continuous leakage setting. And it is desirable that the designed schemes can resist the leakage attacks. In this paper, to achieve better continuous leakage resilience, a novel construction of continuous leakage-resilient PKE scheme is proposed. The chosen-ciphertext attacks security of our proposed scheme can be proved based on the hardness of the decisional Diffie-Hellman assumption. Our construction tolerates a large key leakage rate, which is one of the best among existing PKE schemes. Moreover, the level of leakage resilience can be adjusted based on the specific requirements in real-world applications. The analyses demonstrate that our proposal also enjoys low computational overheads, outperforming the existing leakage-resilient PKE schemes.