Efficient chosen‐ciphertext secure public‐key encryption scheme with high leakage‐resilience

Abstract

A leakage-resilient public-key encryption (PKE) scheme provides security even if an adversary obtains some information on the secret key. In recent years, much attention has been focused on designing provably secure PKE in the presence of key-leakage and almost all the constructions rely on an important building block namely hash proof system (HPS). However, in the setting of adaptive chosen-ciphertext attacks (CCA2), there are not many HPS-based leakage-resilient PKE schemes available. Moreover, most of them have an unsatisfactory leakage rate. In this study, the authors propose a new method of constructing leakage-resilient CCA2-secure PKE scheme from any tag-based strongly universal 2 HPS. The striking advantage of the authors scheme is the leakage rate, which is the best one among all known HPS-based indistinguishability key leakage CCA2-secure constructions. In particular, they present an instantiation under the n-linear assumption. In the cases of n = 1 (resp. n = 2), they actually obtain a decisional Diffie-Hellman (DDH)-based [resp. decisional linear (DLIN)-based] PKE scheme, where the leakage rate can be made to 1/4 (resp. 1/6). The authors DDH-based scheme achieves the best leakage rate among all known DDH-based (Cramer-Shoup-type) schemes. Their DLIN-based scheme is the first one that can achieve leakage of L/6 bits without pairing, where L is the length of the secret key.

Efficient KDM-CCA Secure Public-Key Encryption via Auxiliary-Input Authenticated Encryption

“…Tag-Based Hash Proof System: Universal 2 , Extracting, and Key-Homomorphism. Tag-based hash proof system (HPS) was first defined in [19]. The definition is similar to extended HPS [20], but the universal 2 property is slightly different.…”

“…The key difference between tag-based HPS and extended HPS lies in the definition of the universal 2 property [19]. Extended HPS requires (6) to hold for ( , ) ̸ = ( , ), while tag-based HPS requires (6) to hold only for ̸ = .…”

“…Qin et al [19] gave a construction of tag-based HPS from the -LIN assumption. Here we construct a key-homomorphic THPS DDH under the DDH assumption in Figure 6.…”

A Leakage-Resilient CCA-Secure Identity-Based Encryption Scheme

“…In 2013, Li et al [26] provided an efficient leakage-resilient public key encryption, which is formally proved semantically secure against adaptive chosen ciphertext attacks under DDH assumption. Recently, Qin et al [27] proposed a new method to construct leakageresilient CCA2-secure public key encryption scheme from any tag-based strongly universal HPS, which has the better leakage rate. Especially, they provided an instantiation under the n-linear assumption.…”

Continuous leakage–resilient IBE in cloud computing

“…Faced with the problem, Liu et al gave efficient solutions by presenting a new leakage resilient model of PKE under Cramer‐Shoup cryptosystem; the leakage parameter is independent of the message. Qin et al provided a new way to build CCA secure PKE scheme resilient to leakage, which improves the leakage ratio. Kurosawa et al exploited an efficient approach to design CCA secure LR‐PKE schemes.…”