Group signature from lattices preserving forward security in dynamic setting

Abstract

<p style='text-indent:20px;'>We propose the <i>first</i> lattice-based dynamic group signature scheme achieving <i>forward security</i>. Our scheme is proven to be secure against framing attack, misidentification attack and preserves anonymity under the learning with errors (${\mathsf{LWE}}$) and short integer solution (${\mathsf{SIS}}$) assumptions in the random oracle model. More interestingly, our setting allows the group manager to generate distinct certificates to distinct users which can be updated by the users themselves without any interaction with the group manager. Furthermore, our scheme is dynamic where signing key of a user is not fixed during the setup and is issued only at the joining time of the user.