Coding Theory: Recent Results in Covert Communication

Sidharth Jaggi (The Chinese University of Hong Kong)
Sunday, 10.6.2018, 14:30
Taub 601

Covert communication considers the following problem -- if Alice wishes towhisper 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, infading channels). It turns out such natural variation can dramatically impact the capacity -- indeed, in general such variation hurts Eve's detector much more thanit hurts Bob's decoder.

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