Speaker: Yvo Desmedt
Title: Using mathematics to achieve a reliable Internet, secure against conspiring insiders.
Affiliation: Florida State University.
Date: Friday, September 15.
Place and Time: Room 101 - Love Building, 3:35-4:35 pm.
Refreshments: Room 204 - Love Building, 3:00 pm.

Abstract. There is no area of discrete mathematics that is not used in information security. Number theory played a major role in protecting communication between a single sender and a single receiver. In this lecture we focus on several problems that arise when there is more than one sender and/or receiver. For example,

(a) if the sender is a bank, one cannot entrust a single individual to be able to sign multimillion dollar electronic transactions. We discuss why the 1979 idea of using secret sharing is insufficient. Threshold Cryptography introduces a flexible management of the secret key that prevents abuse by untrusted insiders and achieves reliability. It is based on mathematical concepts such as algebraic integers, combinatorics and tensor product of modules, computer science topics as perfect family of hash functions, and security concepts such as secret sharing and zero-knowledge;

(b) when a single sender broadcasts information several potential problems arise. Can certain receivers jam the communication? How can the sender protect privacy without the need to dramatically increase the required bandwidth? In the case of Pay-TV, how can one trace those who leak decryption keys? The combinatorial concepts of cover-free sets, e.g. studied by Erdos et al., allow us to address these concerns.

    No prior knowledge is required to follow the talk.