Seminar - Professor Ashish Khisti

Wednesday, December 3, 2014 9:30 am - 10:30 am EST (GMT -05:00)


Professor Ashish Khisti, ECE, University of Toronto


Secret-Key Generation and Secure Communication at the Physical Layer in Wireless Systems


Recent advances in the physical layer have created new opportunities for securing wireless systems that complement traditional cryptographic approaches. In this talk, I will present my recent work on secret-key generation and secure communication at the physical layer. The first part of the talk will focus on secret-key generation over a non-coherent, two-way, block-fading, wireless channel. We will study a separation-based scheme and establish its optimality in the high signal-to-noise ratio regime.  This coding scheme uses a portion of each coherence block for transmitting training symbols, and the remainder of the coherence block for creating additional shared randomness between the terminals. We will also study training-only schemes which are often considered in the literature, and show that they can be very far from the secret-key capacity in general. 

In the second part of the talk, I will review some capacity results of secure communication in multiple antenna wireless systems, both in the single-user and compound settings. I will present a new "artificial noise alignment" scheme, that aligns artificial noise symbols in the direction of all intended users, and masks information symbols in all the undesired directions, and provides a robust mechanism for using multiple antennas for secure communication. Finally if time permits, I will also discuss how the availability of shared secret-keys, as well as the structure of communication channels can be jointly exploited in certain multiuser wire-tap settings.

Speaker's biography

Ashish Khisti joined the University of Toronto as assistant professor in September 2009, and holds the Canada Research Chair in Wireless Networks. He obtained his BASc degree from Engineering Sciences (Electrical Option) from the University of Toronto and his SM and PhD degrees from the Massachusetts Institute of Technology (MIT), Cambridge, MA in Electrical Engineering and Computer Science. His research interests include Information Theoretic Security, Real-Time Streaming Communication and Statistical Signal Processing. Prof. Khisti is a recipient of the Ontario Early Researcher Award from the province of Ontario, and the Hewlett-Packard Innovation Research award. He serves as an Associate Editor of the IEEE Transactions on Communications.

Invited by Professor Guang Gong