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Zhang L.,East China Normal University | Zhang L.,Rovira i Virgili University | Zhang F.,Nanjing Normal University | Zhang F.,Jiangsu Engineering Research Center on Information Security and Privacy Protection Technology | And 2 more authors.
Information Sciences | Year: 2012

A proxy signature scheme allows a proxy signer to sign messages on behalf of an original signer within a given context. It has lots of practical applications in distributed systems, grid computing, mobile agent applications, distributed shared object systems, global distribution networks, and mobile communications. In the last years, fruitful achievements have been seen in certificateless public key cryptography which has the advantages of no certificate management and no key escrow compared with traditional public key cryptography and identity-based public key cryptography respectively. However, the existing certificateless proxy signature schemes is either insecure or without formal security analysis. In this paper, we formalize the security model of certificateless proxy signature schemes and propose a provably secure certificateless proxy signature scheme with formal security proof under the computational Diffie-Hellman assumption. © 2011 Elsevier Inc. All rights reserved. Source


Zhang L.,Rovira i Virgili University | Qin B.,Rovira i Virgili University | Qin B.,Xian University of Science and Technology | Wu Q.,Rovira i Virgili University | And 3 more authors.
Computer Networks | Year: 2010

Aggregate signatures allow an efficient algorithm to aggregate n signatures of n distinct messages from n different users into one single signature. The resulting aggregate signature can convince a verifier that the n users did indeed sign the n messages. This feature is very attractive for authentications in bandwidth-limited applications such as reverse multicasts and senor networks. Certificateless public key cryptography enables a similar functionality of public key infrastructure (PKI) and identity (ID) based cryptography without suffering from complicated certificate management in PKI or secret key escrow problem in ID-based cryptography. In this paper, we present a new efficient certificateless aggregate signature scheme which has the advantages of both aggregate signatures and certificateless cryptography. The scheme is proven existentially unforgeable against adaptive chosen-message attacks under the standard computational Diffie-Hellman assumption. Our scheme is also very efficient in both communication and computation and the proposal is practical for many-to-one authentication. © 2010 Published by Elsevier B.V. Source


Zhang J.,Nanjing Normal University | Zhang F.,Nanjing Normal University | Zhang F.,Jiangsu Engineering Research Center on Information Security and Privacy Protection Technology
Future Generation Computer Systems | Year: 2015

Abstract As a basic tool, Verifiable Secret Sharing (VSS) has wide applications in distributed cryptosystems as well as secure multi-party computations. A number of VSS schemes for sharing a secret from a finite field, both on threshold access structures and on general access structures, have been available. In this paper, we investigate the verifiably sharing of a secret that is a random element from a bilinear group on vector space access structures. For this purpose, we present an information-theoretical secure VSS scheme, and then convert it to a modified one with improved efficiency. The performance and the security of the proposed schemes are analyzed in detail. Two examples are given to illustrate the applications of our proposed VSS schemes. One is the secure sharing of an organization's private key in Boneh and Franklin's identity-based encryption system, and the other is the distributed key generation and distributed decryption for bilinear ElGamal encryption system, both with vector space access structures. © 2014 Elsevier B.V. Source


Zhang F.,Nanjing Normal University | Zhang F.,Jiangsu Engineering Research Center on Information Security and Privacy Protection Technology | Zhang J.,Nanjing Normal University
Chinese Journal of Electronics | Year: 2014

Verifiable secret sharing VSS is an important technique which has been used as a basic tool in distributed cryptosystems, secure multi-party computations, as well as safe guarding some confidential information such as cryptographic keys. By now, some secure and efficient non-interactive VSS schemes for sharing secrets in a finite field have been available. In this paper, we investigate verifiably sharing of a secret that is an element of a bilinear group. We present an efficient and informationtheoretical secure VSS scheme for sharing such a secret which may be a private key for a pairing based cryptosystem. Our performance and security analysis indicates that the newly proposed scheme is more efficient and practical while enjoys the same level of security compared with similar protocols available. We also demonstrate two typical applications of our proposed VSS scheme. One is the sharing of a secret key of Boneh and Franklin's identity-based encryption scheme, and the other is the sharing or the distributed generation of a secret key of the leakage resilient bilinear ElGamal encryption scheme. Source


Miao S.,Nanjing Normal University | Zhang F.,Nanjing Normal University | Zhang F.,Jiangsu Engineering Research Center on Information Security and Privacy Protection Technology | Li S.,Nanjing Normal University | Mu Y.,University of Wollongong
Information Sciences | Year: 2013

It would be interesting if a signcryption scheme in the standard model could be made certificateless. One of the interesting attempts is due to Liu et al. [Z. Liu, Y. Hu, X. Zhang, H. Ma, Certificateless signcryption scheme in the standard model, Information Sciences 180 (3) (2010) 452-464]. In this paper, we provide a cryptanalysis on this scheme by depicting two kinds of subtle public key replacement attacks against it. Our analysis reveals that it does not meet the basic requirements of confidentiality and non-repudiation. © 2013 Elsevier Inc. All rights reserved. Source

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