Dynamic Fully Anonymous Short Group Signatures [chapter]

Cécile Delerablée, David Pointcheval
2006 Lecture Notes in Computer Science  
Group signatures allow members to sign on behalf of a group. Recently, several schemes have been proposed, in order to provide more efficient and shorter group signatures. However, this should be performed achieving a strong security level. To this aim, a formal security model has been proposed by Bellare, Shi and Zang, including both dynamic groups and concurrent join. Unfortunately, very few schemes satisfy all the requirements, and namely the shortest ones needed to weaken the anonymity
more » ... n. We present an extremely short dynamic group signature scheme, with concurrent join, provably secure in this model. It achieves stronger security notions than BBS, and namely the full anonymity, while still shorter. The proofs hold under the q-SDH and the XDH assumptions, in the random oracle model. Motivations and Related Work Recently, several schemes have been proposed, in order to reduce the computational cost and the size of group signatures. In particular, BBS [6] is the most efficient one, and provides the shortest c Springer-Verlag 2006.
doi:10.1007/11958239_13 fatcat:igrhojlz75fdvfuyacjvi7ynmq