How to Demonstrate Our Presence Without Disclosing Identity? Evidence from a Grouping-Proof Protocol

The recent hot debate on sharing economy has been an emergence in a dynamic ownership economy, which attracts lots of attentions in the news media. The concept and practice of resource sharing have been fast becoming a mainstream phenomenon across the world. People share assets to their friends via Internet or smartphones. Meanwhile, researchers are now beginning to weigh in with deeper analysis in terms of security and privacy, which turn out to be one critical area of argument when sharing the items with others. To securely track the location of an item is of high importance in many mobile applications, which rely heavily on the notion of device proximity. In addition to securely and precisely determining an item’s location, it is also desirable to preserve the privacy and untraceability of the item. Grouping-proof protocols are often used to prove the presence of a group of Provers to the Verifier at the same time. In this paper, we propose a new grouping-proof protocol that is well deployed in proximity identification systems for sharing economy, where each Prover needs to demonstrate its presence to the Verifier without disclosing its real identity. Our protocol is mutually authenticated and secure against all known attacks in a grouping-proof setting. Furthermore, the protocol retains the untraceability of a tag through forward privacy and prevents de-synchronization attacks.