Multicast communication enables the distribution of digital content from a single source to a large audience via a public channel such as the Internet. Broadcasting has applications in sensor networks, pay-TV, software updates and military defence systems to name a few. As these applications will distribute private or sensitive information, multicast protocols must provide data origin authentication.
Broadcast channels have limited bandwidth and may be under the influence of opponents deleting, inserting and reordering data packets. In such a context, the security of authentication protocols relies on two aspects: the opponents' computational powers and the network properties.
In this presentation, we will introduce provable secure protocols providing non-repudiation of the origin of a data stream over an unsecured communication channel. We will emphasize that our constructions provide practical solutions to the stream authentication problem, i.e. the requirements of provable security are compatible with the settings of broadcasting.
Christophe Tartary obtained a Master in Cryptography from University of Limoges, France (2001). He was a PhD candidate within the Department of Computing at Macquarie University (Australia) until August 2007 where he studied authentication protocols for stream authentication. He then joined the Division of Mathematical Sciences at Nanyang Technological University (Singapore) and the Institute for Theoretical Computer Science at Tsinghua University (China) as a research fellow. His research interests include cryptography, multicast security and coding theory.