Voigt, SebastianHochberger, ChristianLiskowsky, Rüdiger2019-06-122019-06-122006978-3-88579-187-4https://dl.gi.de/handle/20.500.12116/23687Virtual rooms and common information spaces are being used more and more frequently. In addition to internet-based solutions, ad-hoc InfoSpaces have been proposed. Their security has not been sufficiently investigated. This paper proposes a new protocol for peer-to-peer data exchange with support for access control for operations in the virtual rooms. Access rights for operations are kept in access control matrices and the security layer allows only operations from clients which are marked as allowed in the access control matrix. The protocol is based on the idea of hiding the identity of all peer-to-peer participants. Thus this protocol offers anonymity and full peer-to-peer support using asymmetric cryptography to distribute the access control matrices. This works without any central authority.enText/Conference Paper1617-5468