The Experts below are selected from a list of 26346 Experts worldwide ranked by ideXlab platform
Zuhua Shao - One of the best experts on this subject based on the ideXlab platform.
-
Improvement of identity-based proxy multi-Signature Scheme
Journal of Systems and Software, 2009Co-Authors: Zuhua ShaoAbstract:A proxy Signature Scheme allows a proxy signer to sign messages on behalf of an original signer, a company or an organization. A proxy multi-Signature Scheme is an extension of the basic proxy Signature Scheme, and permits two or more original signers to delegate their signing powers to the same proxy signer. Recently, Wang and Cao proposed an identity-based proxy multi-Signature Scheme. This Scheme is very simple and efficient since it is an extension of the identity-based aggregate Signature Scheme due to Gentry and Ramzan. Though the identity-based aggregate Signature Scheme of Gentry and Ramzan is secure in the random oracle model, in this paper, we find that the identity-based proxy multi-Signature Scheme of Wang and Cao is not secure unless each proxy secret key can only be used to generate at most one proxy Signature. Finally, we propose an improvement to overcome this weakness, which is more simple and efficient than the identity-based proxy multi-Signature Scheme of Wang and Cao. We show that the improvement is existentially unforgettable in the random oracle model under the computational Diffie-Hellman assumption.
Zhang Jian-zhong - One of the best experts on this subject based on the ideXlab platform.
-
Improved Group Signature Scheme
Computer Engineering, 2010Co-Authors: Zhang Jian-zhongAbstract:This paper analyzes a group Signature Scheme that it has the property of member deletion,points out that Signature open algorithm and validated algorithm are all invalid,and it has redundant data because of Signature parameter setting incorrectly.It improves group Signature Scheme on the basis of it.By attaching the Signature public key to Signature parameters,it resolves the problem of the identity revelation algorithm invalidity.By modifying group centre to trusted centre and removing the group manager entity,it resolves the problem of the group centre excessive power to improve the overall effectiveness of improved Scheme.
-
Cryptanalysis and Improvement of Group Signature Scheme
Computer Engineering, 2009Co-Authors: Zhang Jian-zhongAbstract:Cryptanalysis of a group Signature Scheme based on Chinese remainder theorem shows that it exists security flaws. Aiming at these flaws,this paper puts forward an improved group Signature Scheme. It realizes effective participation and revocation of group members under the condition that keep the group member secret key unaltered. Analysis results show that this Scheme is secure and practicable.
Chienlung Hsu - One of the best experts on this subject based on the ideXlab platform.
-
new nonrepudiable threshold proxy Signature Scheme with known signers
Journal of Systems and Software, 2001Co-Authors: Chienlung HsuAbstract:Based on Kim et al.'s threshold proxy Signature Scheme, Sun proposed an nonrepudiable threshold proxy Signature Scheme with known signers. In Sun's Scheme, actual proxy signers cannot deny the Signatures they have signed. However, his Scheme is vulnerable against the conspiracy attack. Any t malicious proxy signers can collusively derive the secret keys of other proxy signers and impersonate some other proxy signers to generate proxy Signatures. In this paper, we proposed a new nonrepudiable threshold proxy Signature Scheme that overcomes the above weakness. Furthermore, the proposed Scheme is more efficient than Sun's in terms of computational complexities and communication costs.
X U Chunxiang - One of the best experts on this subject based on the ideXlab platform.
-
A New Group Signature Scheme with Unlimited Group Size
Progress on Cryptography, 2004Co-Authors: F U Xiaotong, X U ChunxiangAbstract:Group Signature Schemes are fundamental cryptographic tools that have many practical applications. We found there are some similarities between group Signatures and proxy Signatures. A new group Signature Scheme with unlimited group size is proposed based on the heuristic idea of proxy Signature Scheme with proxy signer’s privacy protection. In this group Signature Scheme the group manager plays the role of the original signer, and the legal group members act as the proxy signers who delegate the original signer’s signing power. The security properties of the new Scheme are also discussed in the paper.
Narn-yih Lee - One of the best experts on this subject based on the ideXlab platform.
-
CRYPTO - Remark on the Threshold RSA Signature Scheme
Advances in Cryptology — CRYPTO’ 93, 1Co-Authors: Tzonelih Hwang, Narn-yih LeeAbstract:Shared generation of secure Signatures, called the threshold Signatures, was introduced by Desmedt and Frankel in 1991. A threshold Signature Scheme is not only a threshold Scheme, but also a Signature Scheme. Therefore, it should possess the properties of both threshold Scheme and digital Signature Scheme. In this paper, we investigate conspiracy attacks on the Desmedt and Frankel's threshold RSA Signature Scheme. We also discuss the requirements of secure threshold Signature Scheme.
