International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Weakly only Unforgeable Signature and Its Application in Group Signature

Sujing Zhou
Dongdai Lin
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Abstract: If a signature scheme is secure in the sense that no forgery on any new message (i.e., a message that has never been signed) is available for any computation restricted adversary, it is said weakly unforgeable (wUF), in contrast to strongly unforgeable (sUF) meaning no new signature on any old message (i.e., a valid signature on the message is already known) is available to such adversaries. sUF signatures are generally considered advantageous over wUF ones because of preference for high level security. But the case may be different when they are employed to construct group signatures. wUF but not sUF signatures, called WoUF signatures in this paper, are investigated in this paper. It is found that by applying a generic construction to WoUF signatures with indirectly-signability and perfectly-unlinkability (also defined in this paper), we can regenerate many efficient group signatures in literature. We also propose improvements to the group signature schemes of CL04, NSN04, KY05, in line with our generic construction.
  title={Weakly only Unforgeable Signature and Its Application in Group Signature},
  booktitle={IACR Eprint archive},
  keywords={Digital Signature, Group Signature, Weakly Unforgeable Signature, Strongly Unforgeable Signature.},
  note={ 13602 received 1 Mar 2007, withdrawn 30 Mar 2007},
  author={Sujing Zhou and Dongdai Lin},