Leakage-Resilient Outsourced Revocable Certificateless Signature with a Cloud Revocation Server

Certificateless public-key system (CL-PKS) is a significant public-key cryptography and it solves both the key escrow and certificate management problems. Outsourced revocable certificateless public-key system (ORCL-PKS) with a cloud revocation server (CRS) not only provides a revocation mechanism, but also further outsources the revocation functionality to the CRS to reduce the computational burden of the key generation center (KGC). Recently, side-channel attacks have threatened some existing conventional cryptography (including CL-PKS). Indeed, adversaries can apply side-channel attacks to derive fractional constituents of private (or secret) keys to damage the security of these cryptographic protocols (or schemes). To withstand such attacks, leakage-resilient cryptography is an attractive approach. However, little research concerns with leakage-resilient certificateless cryptography. In this paper, the first leakage-resilient outsourced revocable certificateless signature (LR-ORCLS) scheme is presented. The proposed scheme allows adversaries to continually derive fractional constituents of private (or secret) keys and possesses overall unbounded leakage property. In the generic bilinear group (GBG) model, our scheme is shown to be existential unforgeable against adversaries. Finally, the comparisons between the proposed scheme and the previous revocable certificateless signature schemes are provided to demonstrate the merits of the proposed scheme.

Applied-Information Technology in Certificateless Proxy Signature Scheme without Bilinear Pairings

This paper researches on the existing certificateless proxy signature scheme, there is almost no certificateless proxy signature scheme based on discrete logarithm up till now. Combining the knowledge of discrete logarithm over finite field and the advantages of certificateless cryptography, this paper proposes an efficient certificateless proxy signature scheme based on the discrete logarithm without bilinear pairings. To avoid the key escrow problem in the id-based cryptosystem and the saving certificate problem in the traditional public cryptography, meet the good properties of the proxy signature, such as unforgery, dependence of the proxy keys, distinguish of the proxy signature and anti-abuse. The scheme does not use the bilinear pairings, and based on the hard problem of discrete logarithm in the finite field, given the proof and discussion of the validity and security of the scheme.

Certificateless Public Key Encryption Scheme with Hybrid Problems and Its Application to Internet of Things

Certificateless cryptography aims at combining the advantages of public key cryptography and identity based cryptography to avoid the certificate management and the key escrow problem. In this paper, we present a novel certificateless public key encryption scheme on the elliptic curve over the ring, whose security is based on the hardness assumption of Bilinear Diffie-Hellman problem and factoring the large number as in an RSA protocol. Moreover, since our scheme requires only one pairing operation in decryption, it is significantly more efficient than other related schemes. In addition, based on our encryption system, we also propose a protocol to protect the confidentiality and integrity of information in the scenario of Internet of Things with constrained resource nodes.