On large scale real time music distribution security, reliability and heterogeneity

Abstract: This thesis presents a system for real-time large scale distributed music distribution, such as radio on the Internet. The existing technologies do not enable the full potential that broadcast media on the Internet can give, such as a very large number of interactive receivers. A technology that can help achieve potential is IP-multicast, which enables broadcast applications to scale to millions of receivers. However, IP-multicast creates new problems that have to be solved for it to be used on the Internet; some of these problems are addressed in this thesis. The system presented in this thesis, mIR - multicast Interactive Radio, has been used as a prototype to implement and examine different solutions to some of the issues of IP-multicast and real time music distribution. These are problems such as heterogeneity, reliability and security. Heterogeneity and reliability are different aspects of the same problem: that IP-multicast is an unreliable Internet transport mechanism. In this thesis different methods for avoiding these problems are described and evaluated. Security in the context of IP-multicast has many aspects. While the problems of confidentiality and authentication have been extensively examined, there are still a few unresolved problems. One of these problems is traitor tracing: how to know the origin of illegal copies of a media object such as a radio transmission. An application of digital watermarking, fingerprinting, can be used to distinguish between different copies of the same media object, but requires that each copy is individually marked. This contradicts the basic property of multicast that ensures its scalability: that everyone receives exactly the same data. We show how we can combine the different goals of fingerprinting and IP-multicast while still maintaining the scalability features of multicast.