Prof. Sidharth Jaggi
Title: Covert communication, or, how to whisper
Abstract: Covert communication tries to answer the following question — if Alice wishes to whisper to Bob while ensuring that the eavesdropper Eve cannot even detect whether or not Alice is whispering, how much can she whisper. Ensuring such a stringent security requirement can be met requires new ideas from information theory, coding theory, and cryptography. In this talk I will survey the state of the existing literature (recent information-theoretic capacity-style results for a variety of settings), and then discuss even more recent results. Specifically, I will highlight: Code constructions: Computationally efficient code constructions that achieve the information-theoretic capacity bounds. Resilience to jamming: In some settings, Eve may not just be a passive eavesdropper, but actively attempt to jam Alice’s communication, even if she isn’t sure whether or not Alice is actually whispering. I will discuss covert communication schemes that are resilient to such malicious jamming. Impact of environmental uncertainty: Often, noise levels on the communication medium are not static, but stochastically varying (for instance, in fading channels). It turns out such natural variation can dramatically impact the capacity — indeed, in general such variation hurts Eve’s detector much more than it hurts Bob’s decoder.
Biography: Sidharth Jaggi received his B. Tech. from I.I.T. Bombay 2000, his M.S. and Ph.D. degrees from the CalTech in 2001 and 2006 respectively, all in EE. He spent 2006 as a Postdoctoral Associate at LIDS MIT. He joined the Department of Information Engineering at the Chinese University of Hong Kong in 2007, where he is now an Associate Professor. His interests lie at the intersection of network information theory, coding theory, and algorithms. His research group thus (somewhat unwillingly) calls itself the CAN-DO-IT team (Codes, Algorithms, Networks: Design and Optimization for Information Theory). Examples of topics he has dabbled in include network coding, sparse recovery/group-testing, covert communication, and his current obsession is with adversarial channels.