Abstract
Distributed Collaborative Editors (DCE) provide computer support for modifying simultaneously shared documents, such as articles; wiki pages and programming source code, by dispersed users. Controlling access in such systems is still a challenging problem, as they need dynamic access changes and low latency access to shared documents. In this paper, we propose a flexible access control model where the shared document and its authorization policy axe replicated at the local memory of each user. To deal with latency and dynamic access changes, we use an optimistic access control technique in such a way that enforcement of authorizations is retroactive. We show that naive coordination between updates of both copies can create security holes on the shared document, by permitting illegal modifications or rejecting legal modifications. Finally, we present a prototype for managing authorizations in collaborative editing work which may be deployed easily on P2P networks.