Vortragender: Yvo Desmedt (Biographie)

Termine:

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.

Biographie:

Yvo Desmedt received his Ph.D. (Summa cum Laude) from the University of Leuven, Belgium (1984). He is presently a professor at Florida State University (Computer Science) and a visiting professor of Information Security at Royal Holloway, University of London. His interests include cryptography, network security and computer security. He has authored more than 100 papers in international conferences and journals. He was program chair of PKC (Public
Key Cryptography) 2003, the 2002 ACM Workshop on Scientific Aspects of Cyber Terrorism and Crypto '94. His first paper that described a potential cyberterrorism scenario dates back to 1983. He is an editor of the Journal of Computer Security, and of Information Processing Letters and is a director of the International Association for Cryptologic Research.

Yvo Desmedt is ranked as the 2nd most prolific author (out of 1165 researchers) in Crypto/Eurocrypt. He has given invited lectures at several conferences and workshops in 5 different continents and more than 100 invited lectures for industry and academia. He is a recipient of the Society of Worldwide Inter-bank Funds Transfer (SWIFT) award.