[Colloq] Fwd: Applied and Interdisciplinary Mathematics Seminar this Friday

[Rajmohan Rajaraman]

A security talk in the Math department that may be of interest to many CCIS folks.

Best,

Rajmohan.

----- On Oct 28, 2015, at 10:08 AM, Christopher King c.king at neu.edu wrote:

Dear Agnes, Rajmohan and Daniel,

I am passing along this notice about our upcoming AIM seminar on Friday. The subject is computational security and so may be of interest to you and others in CCIS, best regards

--Chris


Applied and Interdisciplinary Mathematics Seminar

Location: 511 Lake Hall, Northeastern University
Date: Friday, October 30, 2015
 Time: 12:00 - 1:00pm
(NOTE UNUSUAL DATE AND TIME!)

Speaker: Ken Duffy (MIT Research Laboratory of Electronics)

Title: Guesswork, quantifying computational security

The talk explores the connection among computational security, probability and information theory. The security of many systems is predicated on the following logic: a user selects a string, for example a password, from a list; an inquisitor who knows the list can query each string in turn until gaining access by chancing upon the user's chosen string; the resulting system is deemed to be computationally secure so long as the list of strings is large.

Implicit in that definition is the assumption that the inquisitor knows nothing about the likely nature of the selected string. If instead one assumes that the inquisitor knows the probabilities with which strings are selected, then the random variable of interest is dubbed Guesswork, the number of queries required to identify a stochastically selected string, and the quantification of computational security becomes substantially more involved.

In this talk we review the seminal work of J. Massey (1994) and E. Arikan (1996) on the moments of Guesswork before describing some of our contributions, which start by establishing a Large Deviation Principle (LDP) for Guesswork, which enables direct estimates of the Guesswork distribution. Moreover, as the LDP is a covariant property, it facilitates a significant broadening of the remit of Guesswork to include the computational security of multi-user systems. These developments, as well as others related to information theoretic security, will be discussed. No prior knowledge of the subject will be assumed.

This talk is based on work with M. Christiansen (NUIM), F. du Pin Calmon (MIT) and M. Medard (MIT).

Seminar Website:http://www.northeastern.edu/mcowen/AIMseminar.html

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