A Case for Multi-key Secure Video Proxy: Theory, Design and Implementation

Because of limited server and network capacities in multimedia streaming, proxies are commonly used to cache multimedia objects such that, by accessing nearby proxies, clients can enjoy smaller start-up latencies and reduced packet loss and delay jitters for their requests. However, the use of video proxies increases the risk that multimedia data are exposed to unauthorized access by intruders. In this paper, we present a framework for implementing a secure video proxy or, more generally, a secure proxy architecture. The framework employs a notion of asymmetr ic reversible parametr ic sequences to provide the following security properties: (1) data confidentiality during transmission, (2) end-teend data confidentiality, (3) data confidentiality against proxy intruders, and (4) data confidentiality against member collusion. Our framework is grounded on a multi-key RSA technique such that system resilience against attacks is provably strong given standard computability assumptions. We also propose the use of a set of encryption configuration parameters to trade off proxy encryption throughput against the viewing quality of video by unauthorized parties. Implementation results on a Pentium III/800 MHz machine show that our techniques can simultaneously achieve high encryption throughput and extremely low video quality (in terms of both PSNR and the visual quality of decoded frames) during unauthorized viewing.