Section: New Results

Secure Collaborative Editing

Participants : Mohammed Riyadh Abdmeziem, François Charoy.

Collaborative edition allows a group of entities to simultaneously edit and share the content of a document in real time. To provide the required keying materials, group key management protocols are usually considered in order to secure and encrypt the exchanged data. Indeed, existing fully distributed protocols induce significant overhead. Instead, centralized solutions are preferred for their high efficiency. Nevertheless, these centralized solutions present two main issues. The first issue is related to the broken end-to-end property, considering the central entity has access to the established credentials. The second issue is related to the single point of failure problem. In fact, if the central entity fails, the key establishment process fails too. To address these challenges, we proposed a simple, and yet efficient approach which enhances central-based protocols with both fault tolerance and end-to-end properties. To do so, we considered the group key as composed of two sub-keys. The first sub-key is only known to the members of the group, excluding the central entity, while the second sub-key is distributed and updated by the central entity following membership changes[3], [4]. Our initial assessment shows that the overall complexity of rekeying operations is not negatively impacted. In addition, our approach is backward compatible with existing solutions in the literature.