Multimedia Security in Group Communications: Recent Progress in Wired and Wireless Networks

Multicast is an internetwork service that provides efficient delivery of data from a source to multiple receivers. It reduces the bandwidth requirements of the network and the computational overhead of the host devices. This makes multicast an ideal technology for communication among a large group of participants. Secure group communications involves many service types include teleconferencing, pay TV and realtime delivery of stock quotes. IP multicast is the traditional mechanism to support multicast communications. It uses the notion of a group of members identified with a given group address. When a sender sends a message to this group address, the network uses a multicast routing protocol to optimally replicate the message and forward copies to group members located throughout the network. For many multicast applications, security is one of the most important requirements. Multicast security includes group membership control, secure key distribution and secure data transfer. This paper is an overview of the schemes proposed for group key management, authentication and watermarking in wired networks with fixed members and wireless networks with mobile members.