International Association
for Cryptologic Research

In a group signature scheme, group members are able to sign on behalf of the group. Since the introduction of this cryptographic authentication mechanism, several schemes have been proposed

but only few of them enjoy a security in the standard model. Moreover, those provided in the standard model suffer the recourse to non standard-assumptions, or the expensive cost and bandwidth of the resulting signature.

We provide three practical group signature schemes that are provably secure in the standard model under standard assumptions. The three schemes permit dynamic enrollment of new members while keeping a constant size for both keys and group signatures, and they improve the state-of-the art by several orders of magnitude.