[HGI-News] Mini Seminar Series by Yvo Desmedt

[hgi-news at lists.ruhr-uni-bochum.de]

Liebe Krypto-Interessierten,

Prof. Yvo Desmedt ist zur Zeit Gast am HGI in der Arbeitsgruppe Prof.
Dobbertins. Er hat sich bereit erklärt in den nächsten Wochen ein
vierteiliges Seminar zu dem sehr interessanten Thema "Threshold Cryptography
and Secret Sharing" anzubieten. Bitte beachten Sie, dass jede einzelne
Vorlesung nur jeweils 45-60 min lang ist. Das Seminar steht wie immer allen
offen.

Wie viele von Ihnen wissen ist Dr. Desmedt einer der erfahrensten
Kryptographen überhaupt, und ich bin sicher, dass diese Seminarserie äußerst
interessant sein wird!

Mit besten Grüßen, Christof Paar


============================================================================

    Some Mathematical Aspects of Threshold Cryptography and Secret Sharing

                              Yvo Desmedt
                       Florida State University

ORT UND ZEITEN:

Dienstag,   4.11., 16:00 bis 17:00 Uhr, NA 5/64
Montag,    10.11., 16:00 bis 17:00 Uhr, NA 4/24
Dienstag   11.11., 16:00 bis 17:00 Uhr, NA 5/64
Donnerstag 13.11., 10:00 bis 11:00 Uhr, NA 4/64


ABSTRACT

Secret sharing allows a dealer to distribute shares of a secret such that:

  -) any set of authorized parties can recover the secret from their shares
  -) any non-authorized parties have as much information about the secret as
     they had initially.

Secret sharing combined with cryptography, allows secure distributed
computation. One can, in particular, compute a digital signature jointly in
such a way that no unauthorized set of parties will learn anything new about
the secret (except the digital signature). Secret sharing has other
applications, that enable reliable communications in untrusted networks. To
achieve these properties different algebraic and combinatorial properties
are
introduced.

This series of lectures starts with an introduction to the concepts of
secret
sharing, (in particular threshold schemes), homomorphic secret sharing,
multiplicative secret sharing, zero-knowledge secret sharing, etc.

Algebra has played a major role in Threshold Cryptography. In this context,
the state of the art on homomorphic and multiplicative secret sharing
schemes
is surveyed. Module theory is applied to obtain a redistribution of a secret
without the need for a trusted dealer. Non-interactive secure distributed
computation is then discussed. We also survey the link between secret
sharing
and error-correcting codes and discuss some applications.

Finally, mechanical keys can often be viewed as secret shares without
algebraic properties. We discuss how combinatorics can then be used
to redistribute mechanical secret shares.

REQUIRED BACKGROUND: elementary group and ring theory. The required module
theory will be introduced.



============================================
Prof. Christof Paar
Chair for Communication Security
Dept. of Electr. Eng. & Information Sciences
Ruhr-University Bochum
44780 Bochum, Germany

URL: www.crypto.rub.de