Identity-based encryption with leakage-amplified chosen-ciphertext attacks security

Abstract

Alwen et al. (EUROCRYPT 2010) proposed the formal definition of identity-based hash proof system (IB-HPS). As an independent interest, they showed that a leakage-resilient identity-based encryption (LR-IBE) scheme can be created based on an IB-HPS. That is, a generic construction of LR-IBE scheme with the chosen-plaintext attacks (CPA) security be designed from the IB-HPS. However, in order to further improve the practicability of identity-based encryption (IBE) system, an IBE scheme must have the chosen-ciphertext attacks (CCA) security. Hence, in this paper, a generic construction of LR-IBE scheme with the CCA security is proposed from the IB-HPS. In additional, to design an LR-IBE schemes with an arbitrarily length leakage parameter, we design a novel generic construction of leakage amplified IBE scheme with CCA security, where we only increase the size of private key proportionally, while do not change all other parameters, and the upper bound of permitted leakage can be flexibly controlled by changing the leakage-size parameter. In other words, the length of allowed leakage of our generic construction is determined by the leakage requirements of actual applications.