Hash Proof System with Auxiliary Inputs and Its Application

In this work, we develop a hash proof system with auxiliary inputs (HPSAI), whose performance is as efficient as the underlying hash proof system (HPS). Moreover, we show that our HPSAI is a practical tool for the creation of leakage-resilient public key encryption (LR-PKE). In particular, we obtain a CCA-secure LR-PKE scheme that is able to leak most of the secret key information-theoretically with any hard-to-invert leakage function. Furthermore, our construction enjoys pairing-free and constant ciphertext size.