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The twelfth meeting of the Prague computer science seminar

Václav Matyáš

Secrecy amplification in partially compromised networks

Distribution of cryptographic keys is a cornerstone to most ICT security solutions. Usage of various key (pre-)distribution schemes in networks with an active attacker results in a partially compromised network where some fraction of keys used to protect link communication is known to the attacker.

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March 26, 2015

4:00pm

Auditorium E-107, FEL CTU
Karlovo nám. 13, Praha 2
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Distribution of cryptographic keys is a cornerstone to most ICT security solutions. Usage of various key (pre-)distribution schemes in networks with an active attacker results in a partially compromised network where some fraction of keys used to protect link communication is known to the attacker. The secrecy amplification protocols were proposed to secure again some previously compromised communication links by using non-compromised paths to deliver new secure keys. Design of suitable secrecy amplification protocols remains a challenge in scenarios where a trade-off between necessary resources (e.g., energy necessary for transmission of message) and improvement in the number of secure links must be balanced.

This talk will inspect most promising classes of secrecy amplification protocols. We combine analysis of given protocol participant placement via a simulator and manual post-processing to provide a simpler, practically usable hybrid protocol with less steps and lower communication overhead, yet still better in terms of re-secured links than previously proposed protocols. The talk is based on results published as: A New Approach to Secrecy Amplification in Partially Compromised Networks. R Ošťádal, P Švenda, V Matyáš. Security, Privacy, and Applied Cryptography Engineering (SPACE) 2014. Springer LNCS 8804, pp. 92-109.

Prof. RNDr. Václav Matyáš, M.Sc., Ph.D.

Václav (Vashek) Matyáš is a Professor at the Masaryk University, Brno, CZ, and Vice-Dean for Foreign Affairs and External Relations, Faculty of Informatics. His research interests relate to applied cryptography and security, where he published over 150 peer-reviewed papers and articles, and co-authored several books. He was a Fulbright-Masaryk Visiting Scholar with Harvard University, Center for Research on Computation and Society in 2011-12, and previously he worked also with Microsoft Research Cambridge, University College Dublin, Ubilab at UBS AG, and was a Royal Society Postdoctoral Fellow with the Cambridge University Computer Lab. Vashek edited the Computer and Communications Security Reviews, and worked on the development of Common Criteria and with ISO/IEC JTC1 SC27.

Its program consists of a one-hour lecture followed by a discussion. The lecture is based on an (internationally) exceptional or remarkable achievement of the lecturer, presented in a way which is comprehensible and interesting to a broad computer science community. The lectures are in English.

The seminar is organized by the organizational committee consisting of Roman Barták (Charles University, Faculty of Mathematics and Physics), Jaroslav Hlinka (Czech Academy of Sciences, Computer Science Institute), Michal Chytil, Pavel Kordík (CTU in Prague, Faculty of Information Technologies), Michal Koucký (Charles University, Faculty of Mathematics and Physics), Jan Kybic (CTU in Prague, Faculty of Electrical Engineering), Michal Pěchouček (CTU in Prague, Faculty of Electrical Engineering), Jiří Sgall (Charles University, Faculty of Mathematics and Physics), Vojtěch Svátek (University of Economics, Faculty of Informatics and Statistics), Michal Šorel (Czech Academy of Sciences, Institute of Information Theory and Automation), Tomáš Werner (CTU in Prague, Faculty of Electrical Engineering), and Filip Železný (CTU in Prague, Faculty of Electrical Engineering)

The idea to organize this seminar emerged in discussions of the representatives of several research institutes on how to avoid the undesired fragmentation of the Czech computer science community.