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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.


Yuan H.,Nanjing Normal University | Zhang F.,Nanjing Normal University | Zhang F.,Jiangsu Engineering Research Center on Information Security and Privacy Protection Technology | Huang X.,Singapore Management University | And 3 more authors.
Information Sciences | Year: 2010

A (t, n) threshold signature scheme allows t or more group members to generate signatures on behalf of a group with n members. In contrast to the traditional public key cryptography based on public key infrastructure (PKI) and identity-based public key cryptography (ID-PKC), certificateless public key cryptography (CL-PKC) offers useful properties as it does not require any certificates to ensure the authenticity of public keys and the key escrow problem is eliminated. In this paper, we investigate the notion of threshold signature schemes in CL-PKC. We start by pointing out the drawbacks in the two existing certificateless threshold signature schemes. Subsequently, we present an elaborate description of a generic certificateless (t, n) threshold signature scheme with a new security model. The adversaries captured in the new model are more powerful than those considered in the existing schemes. Furthermore, we establish the simulatability for certificateless threshold signature schemes and prove the relationship between the security of certificateless threshold signature schemes and that of the underlying non-threshold certificateless signature schemes. As an instantiation, we present a concrete certificateless threshold signature scheme based on bilinear maps using the techniques of verifiable secret sharing and distributed key generation. The proposed scheme is shown to be existentially unforgeable against adaptively chosen message attacks assuming the hardness of Computational Diffie-Hellman (CDH) problem. © 2010 Elsevier Inc. All rights reserved.


Zhang L.,Rovira i Virgili University | Qin B.,Rovira i Virgili University | Qin B.,Xi'an 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.


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.


Zhang L.,Rovira i Virgili University | Zhang L.,Nanjing Normal University | Zhang F.,Nanjing Normal University | Zhang F.,Jiangsu Engineering Research Center on Information Security and Privacy Protection Technology | And 3 more authors.
Information Sciences | Year: 2010

Key agreement (KA) allows two or more users to negotiate a secret session key among them over an open network. Authenticated key agreement (AKA) is a KA protocol enhanced to prevent active attacks. AKA can be achieved using a public-key infrastructure (PKI) or identity-based cryptography. However, the former suffers from a heavy certificate management burden while the latter is subject to the so-called key escrow problem. Recently, certificateless cryptography was introduced to mitigate these limitations. In this paper, we first propose a security model for AKA protocols using certificateless cryptography. Following this model, we then propose a simulatable certificateless two-party AKA protocol. Security is proven under the standard computational Diffie-Hellman (CDH) and bilinear Diffie-Hellman (BDH) assumptions. Our protocol is efficient and practical, because it requires only one pairing operation and five multiplications by each party. © 2009 Elsevier Inc. All rights reserved.


Miao S.,Nanjing Normal University | Miao S.,Jiangsu Engineering Research Center on Information Security and Privacy Protection Technology | Zhang F.,Nanjing Normal University | Zhang F.,Jiangsu Engineering Research Center on Information Security and Privacy Protection Technology | Zhang L.,Rovira i Virgili University
Proceedings - 2010 2nd International Conference on Multimedia Information Networking and Security, MINES 2010 | Year: 2010

Certificateless public key cryptography eliminates certificate management in traditional public key infrastructure and solves the key escrow problem in identity-based cryptography. Certificateless signcryption is one of the most important primitives in certificateless public key cryptography which achieves confidentiality and authentication simultaneously. Multi-receiver signcryption signcrypts a message to a large number of receivers. Selvi et al. proposed the first efficient and provably secure certificateless multi-receiver signcryption scheme. Recently, they found the scheme is insecure against the type I adversary and gave an enhanced one. However, we find that their enhanced scheme is still insecure against the type I adversary. In this paper, we present an attack on Selvi et al.'s enhanced scheme. Specifically, we show that a type I adversary can first replace a sender's public key and generate a signcrypted message on behalf of the sender. © 2010 IEEE.


Liu Y.,Nanjing Normal University | Liu Y.,Heilongjiang Research Center for Labor Safety Science and Technology | Zhang F.,Nanjing Normal University | Zhang F.,Jiangsu Engineering Research Center on Information Security and Privacy Protection Technology | Zhang J.,Nanjing Normal University
Information Sciences | Year: 2016

Secret sharing plays an important role in protecting confidential information from being lost, destroyed, or falling into wrong hands. Verifiable multi-secret sharing enables a dealer to share multiple secrets among a group of participants such that the deceptive behaviors of the dealer and the participants can be detected. In this paper, we analyze the security of several recently proposed verifiable multi-secret sharing schemes. We show that these schemes cannot withstand some deceptive behaviors of the dealer, and hence fails to satisfy the basic requirement of secure verifiable secret sharing schemes. After that, we present two improved verifiable multi-secret sharing schemes. Our new schemes can not only resist cheating by the dealer or participants, but also remove the use of private channels. © 2015 Published by Elsevier B.V.


Zhang J.,Nanjing Normal University | Zhang F.,Nanjing Normal University | Zhang F.,Jiangsu Engineering Research Center on Information Security and Privacy Protection Technology
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

Verifiable secret sharing (VSS) is a fundamental tool of threshold cryptography and distributed computing. A number of VSS schemes for sharing a secret that is an element of a finite field, either on threshold access structures or on general access structures have been available. In this paper, we study the verifiably sharing of a random element of a bilinear group on vector space access structures. We propose such two information-theoretical secure schemes: a basic scheme and a modified one with improved efficiency. The basic one is more general for applications while the modified one has a smaller computational cost compared with the basic one. The computational cost as well as the security analysis for the proposed schemes are presented. © 2014 Springer International Publishing.


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.


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.

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