Flexi-Tunes: An integrated architecture based on flexible tunnels for secure and scalable multimedia comm

Security is now the biggest concern for communicating over the Internet. Over the past decade several protocols (such as SSH, SSL) have emerged that use complex cryptographic algorithms to achieve privacy. While the use of these protocols has been widely popular for non-real-time data, their use for securing real-time multimedia has been questionable. In this dissertation, we argue (using quantitative results) that the current security protocols may not be suitable to handle multimedia. The compute intensive crypto algorithms and additional overhead introduced by security, eventually takes a toll on such applications. Thus novel mechanisms need to be envisioned that can balance the security properties of these protocols with their performance drawbacks. In this respect, we propose Selective Encryption, where an application intelligently secures only a part of its data, while still maintaining its privacy.; We have developed Flexi-Tunes as a research platform that offers such a selective encryption service to its applications. A distinguishing characteristic of Flexi-Tunes is that it replaces the point-to-point tunnels typically used by security protocols with packet switched tunnels, which increases scalability. Simulations using this platform demonstrate 170% improvements in bandwidth utilization. While this approach improves performance, the problem faced by applications to select the right components to secure is nontrivial. In this respect, we discuss one solution for selectively securing a popular multimedia application like mp3. We prove that the privacy of an mp3 stream is guaranteed even if only 4% of it has been secured.; Finally, we also discuss the Quality of Service issues faced by multimedia applications when streamed over secure tunnels offered by Virtual Private Networks (VPNs) and develop an efficient graph algorithm for connecting VPN nodes over the Internet using bandwidth reserved links. Every VPN node only specifies the maximum traffic it can send/receive and the algorithm finds the most optimal way to connect them such that the bandwidth provisioning cost is close to optimal.