Enhancing privacy in collaborative scenarios utilising a flexible proxy layer

In this paper we present our approach for a flexible proxy layer, allowing the parallel use of anonymous and direct network communication depending on specific scenarios or user preferences. The requirements are derived from scenarios from the european research project di. me, targeting to support end users in keeping control of their personal data and digital footprints. In the targeted scenarios, the use of anonymous network communication is an essential prerequisite for certain use cases (e.g. like pseudonymous communication), because of the special architecture, where each user has its own server holding his private data. Especially, the presented approach solves linkability which could arise when using SSL certificates/x.509 certificates and addresses various potential attacks. A detailed specification is given and important implementation details are addressed.