Speaker: Dr. Ashish Khisti

Affiliation: Assistant Professor, Canada Research Chair (Tier II), University of Toronto

Seminar Title: "Secret-Key Generation and Secure Communication at the Physical Layer in Wireless Systems"
Abstract:
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.

Short Bio:
Ashish Khisti joined the University of Toronto as assistant professor in September 2009 and has been a Canada Research Chair (Tier II) in Wireless Networks since January 2013. He obtained his BASc degree from Engineering Sciences (Electrical Option) from the same university and his SM and PhD degrees from the Massachusetts Institute of Technology (MIT), Cambridge, MA in Electrical Engineeing and Computer Science. Between September 2008 to August 2009 he was with the Deutsche Telekom Laboratories, California.  
He is a recipient of the HP-IRP award in 2011 and 2012 and an Ontario Early Researcher Award (2012). For his graduate studies, he received the NSERC doctoral fellowship and the HP/MIT alliance fellowship. He is also a recipient of the Morris Joseph Levin Masterworks award and the Harold Hazen teaching assistant award from the EECS department at MIT.

http://www.comm.utoronto.ca/~akhisti/khisti.htm