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Security mechanisms in the traditional cryptography have been modeled under the assumption that secret values keys are completely hidden to an adversary. Indeed, a number of side-channel attacks e.g., timing, power, fault, etc. have been demonstrated to obtain partial information about secret keys. Leakage-resilient cryptography is a countermeasure to withstand side-channel attacks. Recently, a large number of leakage-resilient cryptographic schemes or protocols have been proposed to resist various side-channel attacks. Up to now, no work has been done on leakage-resilient identity-based signature LR-IBS. In this article, we propose the first LR-IBS scheme based on Galindo and Vivek's leakage-resilient signature. In the generic bilinear group model, we formally prove that our LR-IBS scheme possesses existential unforgeability against identity and adaptive chosen message attacks under the continual leakage model. Copyright © 2016 John Wiley & Sons, Ltd.

Quite recently, Shen et al. proposed a revocable certificateless public key encryption RCL-PKE scheme in the standard model, in which the key generation center KGC can efficiently revoke misbehaving or compromised users. However, their scheme was shown to be insecure. Moreover, the work of revoking users is executed only by the KGC, and their scheme requires high computation cost. In this paper, we propose the first secure RCL-PKE scheme with a delegated revocation authority in the standard model. We emphasize that the delegated revocation authority shares the responsibility for user revocation to reduce the load of the KGC and provide the revocation flexibility. When compared with Shen et al.'s scheme, our scheme has better performance in terms of each user's private key size and computation cost. Under the decisional bilinear Diffie-Hellman and collision-resistant hash function assumptions, we demonstrate that the proposed RCL-PKE scheme is semantically secure in the standard model. Copyright © 2015 John Wiley & Sons, Ltd.

In 2011, Zhao et al. presented a new security model of group key agreement GKA by considering ephemeral secret leakage ESL attacks. Meanwhile, they proposed a strongly secure GKA protocol under the new model. In this paper, two security weaknesses on their protocol are pointed out and remedied, in which, their GKA protocol must rely on a signature scheme with existential unforgeability under adaptive chosen message attacks UF-ACMA to achieve the security goals of authenticated key exchange and mutual authentication in the new model. We argue and illustrate that a UF-ACMA secure signature scheme is insufficient to promise the security goals because the employed signature scheme does not consider the ESL attacks. For providing authentication functionality of some future cryptographic mechanisms e.g., authenticated GKA protocols, authenticated key agreement protocols, and authentication schemes resistant to the ESL attacks, we define a novel security notion for digital signature schemes, termed existential UF-ACM and ephemeral secret leakage attacks. On the basis of Schnorr's signature scheme, we propose the first UF-ACM and ephemeral secret leakage attacks secure signature scheme. We demonstrate that the proposed scheme is provably secure under the hardness of computing discrete logarithms in the random oracle model. Copyright © 2014 John Wiley & Sons, Ltd.

In the past, many ID-based signature (IBS) schemes based on the integer factorization or discrete logarithm problems were proposed. With the progress on the development of quantum technology, IBS schemes mentioned above would become vulnerable. Recently, several IBS schemes over lattices were proposed to be secure against attacks in the quantum era. As conventional public-key settings, ID-based public-key settings have to offer a revocation mechanism to revoke misbehaving or malicious users. However, in the past, little work focuses on the revocation problem in the IBS schemes over lattices. In this article, we propose a new revocable IBS (RIBS) scheme with short size over lattices. Based on the short integer solution (SIS) assumption, we prove that the proposed RIBS scheme provides existential unforgeability against adaptive chosen-message attacks. As compared to the existing IBS schemes over lattices, our RIBS scheme has better performance in terms of signature size, signing key size, and the revocation mechanism with public channels.

A signature scheme is one of the important primitives in modern cryptography, which may offer functionalities of user identification, non-repudiation, and message authentication. With the advent of identity (ID)-based public key systems with bilinear pairings defined on elliptic curves, many ID-based signature schemes have been proposed. Like certificate-based public key systems, any ID-based public key system must provide a revocation method to revoke misbehaving users. There was little work on studying the revocation problem of ID-based public key systems, and no ID-based signature scheme deals with how to revoke the signing ability of misbehaving users. Quite recently, Tseng and Tsai presented a practical revocation mechanism using a public channel for ID-based public key systems. In this paper, we adopt Tseng and Tsai's revocation concept to define the new framework and security notions of revocable ID-based signature (RIBS) scheme and propose the first RIBS scheme in the standard model. Under the computational Diffie–Hellman assumption, we demonstrate that the proposed RIBS scheme is provably secure while remaining efficient for signing and verification as compared with previously proposed ID-based signature schemes. Copyright © 2013 John Wiley & Sons, Ltd.

Pairing-based public key systems have recently received much attention because bilinear property contributes to the designs of many cryptographic schemes. In 2002, Mitsunari et al. proposed the first pairing-based traitor tracing scheme with constant-size ciphertexts and private keys. However, their scheme has been shown to be insecure for providing traitor tracing functionality. Recently, many researches still try to propose efficient pairing-based traitor tracing schemes in terms of ciphertext and private key sizes. In this paper, we present a security claim for the design of pairing-based traitor tracing schemes. For a pairing-based traitor tracing scheme with constant-size ciphertexts and private keys, if the decryption key is obtained by some pairing operations in pairing-based public key systems, the scheme will suffer from a linear attack and cannot provide the traitor tracing functionality. Finally, we apply our security claim to attack a pairing-based traitor tracing scheme proposed by Yang et al. to demonstrate our result. Our security claim can offer a notice and direction for designing pairing-based traitor tracing schemes. Copyright © 2012 John Wiley & Sons, Ltd.

Family quarrels over inheritance, although not new, have been featured prominently in the news in recent years. Thus, the issue of executing wills for the purpose of dividing inheritance is worth investigating. Acrimony caused by family disputes or distribution of inheritance has a negative impact on society. Thus, we seek to construct a method of constructing a secure and private escrow will. The concept of secret sharing was proposed by Shamir and Blakley in 1979. Our method seeks to alleviate problems associated with secret sharing. We divide secret S into n pieces and distribute those pieces to n specific objects. We call the n owners the shadows. We then reconstruct these shadows and retrieve the original main key. Our method functions on the basis of the secret sharing mechanism. The proposed scheme combines the convenience of the Internet with cryptology technologies to solve the security problems of the online wills. It not only reduces cost and improves performance, but also prevents family infighting. Copyright © 2011 John Wiley & Sons, Ltd.