Paper 2004/148

Provably Secure Delegation-by-Certification Proxy Signature Schemes

Zuowen Tan and Zhuojun Liu


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.

Available format(s)
Public-key cryptography
Publication info
Published elsewhere. Unknown where it was published
digital signatureproxy signaturebilinear mapco-GDH groupsprovably secure
Contact author(s)
ztan @ mmrc iss ac cn
2004-07-07: received
Short URL
Creative Commons Attribution


      author = {Zuowen Tan and Zhuojun Liu},
      title = {Provably Secure Delegation-by-Certification Proxy Signature Schemes},
      howpublished = {Cryptology ePrint Archive, Paper 2004/148},
      year = {2004},
      note = {\url{}},
      url = {}
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