Secret Key Agreement: General Capacity and Second-Order Asymptotics


Shun Watanabe


Tokyo University of Agriculture and Technology
Department of Computer and
Information Sciences
4-8-1 Harumicho
Fuchu, Tokyo 183-0057


Friday, 4 December 2015, 11:00 to 12:00



Abstract: We revisit the problem of secret key agreement using interactive public communication for two parties and propose a new secret key agreement protocol. The protocol attains the secret key capacity for general observations and attains the second-order asymptotic term in the maximum length of a secret key for independent and identically distributed observations. In contrast to the previously suggested secret key agreement protocols, the proposed protocol uses interactive communication. In fact, the standard one-way communication protocol used prior to this work fails to attain the asymptotic results above. Our converse proofs rely on a recently established upper bound for secret key lengths. Both our lower and upper bounds are derived in a single-shot setup and the asymptotic results are obtained as corollaries (it is a joint work with M. Hayashi and H. Tyagi (arXiv:1411.0735).

Bio: Shun Watanabe received B.E., M.E., and Ph.D. degree from Tokyo Institute of Technology in 2005, 2007, and 2009, respectively. During April 2009 to February 2015, he was an assistant professor of the Department of Information Science and Intelligence Systems at the University of Tokushima.  During April 2013 to March 2015, he was a visiting assistant professor of the Institute for Systems Research at the University of Maryland, College Park. Since February 2015, he has been a tenure track associate professor of the Department of Computer and Information Sciences at Tokyo University of Agriculture and Technology.