# The Fields Institute

Industrial Mathematics Seminar Series

#### Thursday, May 13, 1999

5:00 - 7:30 p.m.

Room 230, The Fields Institute

**SCHEDULE**

__Cryptography__
5:00 - 6:00 p.m.

*"Distributed Trust Mechanisms in Information Security and Cryptography"*

Doug R. Stinson, Director, Centre for Applied Cryptographic Research (CACR),
University of Waterloo

6:30 - 7:30 p.m.

*"The Mathematics of Public-Key Cryptography"*

Gary Walsh, Research Mathematician, Communications Security Establishment,
Ottawa

## ABSTRACTS

*"Distributed Trust Mechanisms in Information Security and Cryptography"*

Doug R. Stinson, Director, Centre for Applied Cryptographic Research (CACR),
University of Waterloo

In many practical situations it is undesirable to entrust one
individual person with sensitive or secret information, or with the ability
to carry out a sensitive action. This motivates the consideration of shared
control schemes, which can be realized using methods of secret sharing. In
a secret sharing scheme, knowledge of a predetermined secret is shared among
several people in such a way that a specified quorum is required in order
for the secret value to be computed. In this talk, we discuss some of the
mathematical techniques used to construct secret sharing schemes, and present
several examples of how secret sharing schemes can be used to facilitate various
types of distributed trust mechanisms.

*"The Mathematics of Public-Key Cryptography"*

P. Gary Walsh, Research Mathematician, Communications Security Establishment,
Ottawa

In recent years there has been an enormous growth in the number of implementations
of Public-Key Cryptography worldwide. The applications of this technology
are extensive, as it provides an assortment of privacy and authentication
services which were essentially not available previously. In this talk we
discuss the security provided by these systems, in particular the underlying
Mathematics which is needed to measure the level of security provided. This
talk is intended for a general audience.

## SPEAKERS

*Doug R. Stinson* is currently a Professor in Department of
Combinatorics and Optimization, University of Waterloo and holder of the NSERC/Certicom
Industrial Research Chair in Cryptography. From 1990 to 1998, Dr. Stinson
held academic positions at the University of Nebraska, and between 1981 to
1990 at the University of Manitoba. Dr. Stinson obtained his Ph.D. degree
in 1981 from the University of Waterloo.

*P. Gary Walsh*
is currently a Research Mathematician at Communications Security Establishment,
an Adjunct Professor at the University of Ottawa. His main interests are in
Diophantine Analysis, Computational aspects of algebraic curves and connections
of Number Theory to Cryptography. Dr. Walsh obtained his Ph.D. from the University
of Waterloo in 1994 and held an NSERC Postdoctoral Fellowship, 1994 to1996.

**OTHER INFORMATION**

The Industrial Mathematics Seminar is offered to any interested participant
-- no reservation is necessary.