Dynamic fully anonymous short group signatures

C Delerablée, D Pointcheval - International Conference on Cryptology in …, 2006 - Springer
C Delerablée, D Pointcheval
International Conference on Cryptology in Vietnam, 2006Springer
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 notion. We present an extremely …
Abstract
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 notion.
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.
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