Revision with unchanged content. Peer-to-Peer (P2P) video conference systems receive more attention recently due to their distinctive advantages over traditional server-based systems like the H.323 systems. Security is of primary concern for these systems when running over the Internet. Basically matured security architectures, which have been broadly employed in client/server systems, are not suitable for P2P systems because of different system approaches used. This book is the first one devising an appropriate security architecture to protect P2P meetings. It has well addressed two vital issues within the architecture: distributed group key management and real-time video encryption. With the state-of-art solutions and clarity of presentation, this book is a valuable resource for both advanced students and researchers who have interests to work on P2P networking and multimedia security.