Highly-Efficient Fully-Anonymous Dynamic Group Signatures

Group signatures are a central tool in privacy-enhancing cryptography, which allow members of a group to anonymously produce signatures on behalf of the group. Consequently, they are an attractive means to implement privacy-friendly authentication mechanisms. Ideally, group signatures are dynamic and thus allow to dynamically and concurrently enroll new members to a group. For such schemes, Bellare et al. (CT-RSA»05) proposed the currently strongest security model (BSZ model). This model, in particular, ensures desirable anonymity guarantees. Given the prevalence of the resource asymmetry in current computing scenarios, i.e., a multitude of (highly) resource-constrained devices are communicating with powerful (cloud-powered) services, it is of utmost importance to have group signatures that are highly-efficient and can be deployed in such scenarios. Satisfying these requirements in particular means that the signing (client) operations are lightweight.