Improvement and Member Deletion of Camenisch's Group Signature Scheme
Zhenjie Huang · Chinese Journal of Computers · 2004
How to shorten the length of group signature and how to delete group members are two most important issues that stand in the way of real-world applications of group signatures.In this paper, an improvement of Camenisch's group signature scheme is made by improving the 1-out-of-n signature of knowledge used in the group signature.The improvement shortens the length of signature of knowledge to shorten the length of group signature.As a result, the signatures in the improved scheme is an (n+5)-tuple, contrasted against a (2n+4)-tuple of the original, and accordingly the lengths of the signatures of the improvement is about a half that of the original.Furthermore, a forward-secure member deletion scheme, using the Public-Key State List and the Trusted Timestamp, is proposed, thus the improper view that Certificate Revocation List (CRL) approach is unsuitable for group signatures is corrected.The proposed member deletion scheme is efficient, since it increases neither the computational complexity nor the length of the signatures of the original scheme.