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Breaking and Repairing Trapdoor-free Group Signature

Journal Article


Abstract


  • Group signature schemes allow a member of a group to sign messages anonymously on behalf

    of the group. In case of later dispute, a designated group manager can revoke the anonymity and identify

    the originator of a signature. In Asiacrypt 2004, Nguyen and Safavi-Naini proposed a group signature

    scheme that has a constant-size public key and signature length, and more importantly, their group

    signature scheme does not require trapdoor. Their scheme is very eñcient and the sizes of signatures are

    shorter compared to the existing schemes that were proposed earlier. In this paper, we point out that

    Nguyen and Safavi-Naini's scheme is insecure. In particular, we provide a cryptanalysis of the scheme

    that allows a non-member of the group to sign on behalf of the group. The resulting group signature can

    convince any third party that a member of the group has indeed generated such a signature, although

    none of the members has done it. Therefore, in case of dispute, the group manager cannot identify who

    has signed the message. We also provide a new scheme that does not suîer from this problem.

UOW Authors


  •   Huang, Xinyi (external author)
  •   Susilo, Willy
  •   Mu, Yi (external author)
  •   Zhang, Futai (external author)

Publication Date


  • 2007

Citation


  • Huang, X., Susilo, W., Mu, Y. & Zhang, F. (2007). Breaking and Repairing Trapdoor-free Group Signature. Journal of Computer Science and Technology, 22 (1), 71-74.

Scopus Eid


  • 2-s2.0-33847058772

Ro Metadata Url


  • http://ro.uow.edu.au/infopapers/3029

Number Of Pages


  • 3

Start Page


  • 71

End Page


  • 74

Volume


  • 22

Issue


  • 1

Abstract


  • Group signature schemes allow a member of a group to sign messages anonymously on behalf

    of the group. In case of later dispute, a designated group manager can revoke the anonymity and identify

    the originator of a signature. In Asiacrypt 2004, Nguyen and Safavi-Naini proposed a group signature

    scheme that has a constant-size public key and signature length, and more importantly, their group

    signature scheme does not require trapdoor. Their scheme is very eñcient and the sizes of signatures are

    shorter compared to the existing schemes that were proposed earlier. In this paper, we point out that

    Nguyen and Safavi-Naini's scheme is insecure. In particular, we provide a cryptanalysis of the scheme

    that allows a non-member of the group to sign on behalf of the group. The resulting group signature can

    convince any third party that a member of the group has indeed generated such a signature, although

    none of the members has done it. Therefore, in case of dispute, the group manager cannot identify who

    has signed the message. We also provide a new scheme that does not suîer from this problem.

UOW Authors


  •   Huang, Xinyi (external author)
  •   Susilo, Willy
  •   Mu, Yi (external author)
  •   Zhang, Futai (external author)

Publication Date


  • 2007

Citation


  • Huang, X., Susilo, W., Mu, Y. & Zhang, F. (2007). Breaking and Repairing Trapdoor-free Group Signature. Journal of Computer Science and Technology, 22 (1), 71-74.

Scopus Eid


  • 2-s2.0-33847058772

Ro Metadata Url


  • http://ro.uow.edu.au/infopapers/3029

Number Of Pages


  • 3

Start Page


  • 71

End Page


  • 74

Volume


  • 22

Issue


  • 1