Title: Digital security of physical objects: theory and practice

S. Voloshynovskiy, University of Geneva, Switzerland

In the last years, there is a strong tendency to introduce well-established and theoretically-proven digital security technologies into the analogue physical world, where proprietary technologies are still dominating. In this talk, I present a framework for the security of physical objects based on the optical features of physical objects. The proposed framework consists of three stages: (a) object recognition, (b) verification of object design with respect to the original template and (c) verification of object authenticity based on uncloneable optical features. All three stages are based on imaging facilities of existing mobile phones where the verification is performed by the end users. I will show how one can solve the above problems based on Bag-of-Words (BOW) framework, which has been widely used in content search systems, biometric applications and more recently in multimedia security applications. Modern BOW based systems can easily handle large-scale search or recognition problems, even on mobile phones. Nowadays, the design of existing BOW-based systems is based on memory/complexity considerations in view of the large-scale nature of the search problem. It includes a lot of heuristics and engineering, where performance is mostly evaluated by testing on (large) databases, and empirically compared for different descriptor classes and encoding algorithms. The presentation aims at establishing a better understanding of the impact of different elements of BOW systems such as the robustness of descriptors, accuracy of assignment and encoding, descriptor compression and pooling and finally decoding. We will demonstrate some information-theoretic limits of BOW system performance. The experimental results on real images and descriptors confirm our theoretical findings.


Sviatoslav Voloshynovskiy (IEEE Senior Member'11) received the Radio Engineer degree from Lviv Polytechnic Institute, Lviv, Ukraine, in 1993 and the Ph.D. degree in electrical engineering from the State University "Lvivska Polytechnika," Lviv, Ukraine, in 1996. From 1998 to 1999, he was a visiting scholar with the University of Illinois at Urbana-Champaign. Since 1999, he has been with the University of Geneva, Switzerland, where he is currently an Associate Professor with the Department of Computer Science and head of the Stochastic Information Processing group. His current research interests are in the information-theoretic aspects of digital data hiding, content fingerprinting, physical object security, stochastic image modeling and machine learning. He has co-authored over 250 journal and conference papers in these areas and holds twelve patents. He is Associate Editor for IEEE Transactions on Information Forensics and Security, Eurasip Journal on Information Security and an elected member of the IEEE Information Forensics and Security Technical Committee (2011-2013) where he is area chair in information-theoretic security. He has served as a consultant to private industry in the above areas.