Cryptology ePrint Archive: Report 2004/148

Provably Secure Delegation-by-Certification Proxy Signature Schemes

Zuowen Tan and Zhuojun Liu

Abstract: In this paper, we first show that previous proxy signature schemes by delegation with certificate are not provably secure under adaptive-chosen message attacks and adaptive-chosen warrant attacks. The schemes do not provide the strong undeniability. Then we construct a proxy signature scheme by delegation with certificate based on Co-GDH group from bilinear map. Our proxy signature scheme is existentially unforgeable against adaptive-chosen message attacks and adaptive-chosen warrant attacks in random oracle model. We adopt a straight method of security reduction in which our scheme's security is reduced to hardness of the computational co-Diffie-Hellem problem. The proposed signature scheme is the first secure delegation-by-certificate proxy signature based on co-GDH groups from bilinear maps under the formal security model in random oracle model.

Category / Keywords: public-key cryptography / digital signature, proxy signature,bilinear map, co-GDH groups, provably secure

Date: received 24 Jun 2004

Contact author: ztan at mmrc iss ac cn

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Version: 20040707:071959 (All versions of this report)

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