Topics in Cryptology — CT-RSA 2002

Volume 2271 of the series Lecture Notes in Computer Science pp 218-235


Co-operatively Formed Group Signatures

  • Greg MaitlandAffiliated withInformation Security Research Centre, Queensland University of Technology
  • , Colin BoydAffiliated withInformation Security Research Centre, Queensland University of Technology

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Group signatures and their applications have received considerable attention in the literature in recent times. Substantial gains have been made with respect to designing provably secure and efficient schemes. In practice, as with all signature schemes, deploying group signature schemes requires the group member’s signing keys to be both physically and electronically secure from theft. Smartcards or similar devices are often offered as a solution to this problem.

We consider the possibility of co-operatively forming group signatures so as to balance the processing load between a modestly performed secure device and a much more powerful workstation. The constructions are based on the observation that several recent group signature schemes have adopted a structure which utilises two values in signature creation - a private signing key and a group membership certificate. We describe a co-operative group signature scheme based on a recently proposed scheme as well as a ‘wallet with observer’ variant.