Group communication is a fundamental paradigm in modem distributed services, with applications in domains such as content distribution, distributed games, and collaborative workspaces. Despite the increasing interest in group-based services and the latest developments in efficient and reliable multi cast, the secure management of groups remains a major challenge for group communication.
In this thesis we propose security and trust mechanisms for supporting secure management of groups within the contexts of controlled and of self-organizing settings.
Controlled groups occur in services, such as multi cast software delivery, where an authority exists that enforces a group membership policy. In this context we propose a secure group key management approach which assures that only authorized users can access protected group resources. In order to scale to large and dynamic groups, the key management scheme must also be efficient. However, security and efficiency are competing requirements. We address this issue by proposing two flexible group key management schemes which can be configured to best meet the security and efficiency requirements of applications and services. One of the schemes can also be dynamically tuned, at system runtime, to adapt to possible requirement changes.
Self-organizing groups occur in services, such as those enabled by peer-to-peer (P2P) and wireless technologies, which adopt a decentralized architecture. In the context of self-organizing groups, with no authority to dictate and control the group members' interactions, group members might behave maliciously and attempt to subvert other members in the group. We address this problem by proposing a reputation-based trust management approach that enables group members to distinguish between well-behaving and malicious members.
We have evaluated our group key management and trust mechanisms analytically and through simulation. The evaluation of the group key management schemes shows cost advantages for rekeying and key storage. The evaluation of the reputation-based trust management shows that our trust metric is resilient to group members maliciously changing their behavior and flexible in that it supports different types of trust dynamics. As a proof of concept, we have incorporated our trust mechanism into a P2P-based intrusion detection system. The test results show an increase in system resiliency to attacks.
Linköping: Linköping University Electronic Press , 2005. , 22 p.
2005-11-09, Visionen, hus B, Campus Valla, Linköpings universitet, Linköping, 10:15 (English)