Vashek (Vaclav) Matyas

Centre for Research on Cryptography and Security
Faculty of Informatics
Masaryk University                      
Botanicka 68a                        
602 00 Brno - Czech Republic             E-mail: LastName at

GPG/PGP keys - operational (GPG), old (PGP)

Office hours: Mon 11:00-50 & Tue 15:15-50.

Current activities:

Analyzing outputs of crypto primites, where we analyze outputs of various crypto primitives for their properties, primarily statistical ones. Our recent results published as
The Return of Coppersmith’s Attack: Practical Factorization of Widely Used RSA Moduli (ROCA) received the Real-World Impact Award at the 2017 ACM CCS conference. Measuring Popularity of Cryptographic Libraries in Internet-Wide Scans was presented at ACSAC 2017. Prior to that we published our RSA key fingerprinting findings as The Million-Key Question – Investigating the Origins of RSA Public Keys won the best paper award at Usenix Security 2016! Check the previous link for additional resources to this paper, including an online key classification tool. Our work also includes examinations of statistical tests as such, involving also significant speed-up of NIST STS and interpretation of the tests. Most recent improvements are described (and algorithms provided) in Optimizing the NIST Statistical Test Suite and the Berlekamp-Massey Algorithm. Our webpage on Faster randomness testing shows some papers on both the speed-ups and also on the interpretation of results. Our paper Constructing empirical tests of randomness (presented at SECRYPT 2014) shows some results for the eSTREAM candidates and other results are shown in the paper Determining Cryptographic Distinguishers for eStream and SHA-3 Candidate Functions with Evolutionary Circuits (extended version of our SECRYPT 2013 paper). Security of random number generation with our work Towards True Random Number Generation in Mobile Environments from NordSec 2009 (paper download), and earlier work with more experimental results appeared in paper The Sources of Randomness in Mobile Devices, NordSec 2007 (paper download).

Security of wireless sensor networks, with focus on security protocols, intrusion detection and also privacy. We focus on examination of various attacker approaches and models, see the extended version of our CANS 2016 paper Attackers in Wireless Sensor Networks Will Be Neither Random nor Jumping - Secrecy Amplification Case. We also presented very interesting protocol designs for secrecy amplification in wireless sensor networks in our paper On Secrecy Amplification Protocols presented at the 9th WISTP International Conference on Information Security Theory and Practice (WISTP’2015). "Improving Intrusion Detection Systems for Wireless Sensor Networks" is our proposal of a framework for IDS parameter setting in wireless sensor networks, presented at ACNS 2014. Conflicts between Intrusion Detection and Privacy Mechanisms for Wireless Sensor Networks is our article in IEEE Security & Privacy 11.5 (2013), "An Adaptive Security Architecture for Location Privacy Sensitive Sensor Network Applications" is our design presented in a paper at LightSec 2013 - Lightweight Cryptography for Security and Privacy. "Multi-Objective Optimization of Intrusion Detection Systems for Wireless Sensor Networks" was presented at the 12th European Conference on Artificial Life (ECAL 2013). Related starting discussion of issues in the area of privacy and IDSs in WSNs can be found in our paper Attack detection vs. privacy - How to find the link or how to hide it?, presented at the 2011 Security Protocols Workshop. "Two Improvements of Random Key Predistribution for Wireless Sensor Networks" was presented at the 8th International Conference on Security and Privacy in Communication Networks (SecureComm 2012); "Evolutionary Design of Message Efficient Secrecy Amplification Protocols" then was our work presented at 15th European Conference on Genetic Programming (EuroGP 2012); and "On the Credibility of Wireless Sensor Network Simulations: Evaluation of Intrusion Detection System" work presented at SIMUTools 2012. Our work on neighbour-based intrusion detection for wireless sensor setworks, partly presented at the Sixth International Conference on Wireless and Mobile Communications (ICWMC) 2010 in Valencia, Spain, is available as the technical report FIMU-RS-2010-04. Our work on Secrecy Amplification Protocols for Wireless Sensor Networks appears at the ACM WiSec 2009, and other results came out in a book chapter in From Problem to Solution: Wireless Sensor Networks Security by Nova Publishers. Some of the work on group support for authenticated key exchange and on secrecy amplification is in the technical report FIMU-RS-2007-05.

Usable security is one of our fairly recent research areas, with the first publications appearing as a paper "Codes v. People: A comparative usability study of two password recovery mechanisms" at WISTP 2016, our paper "On the impact of warning interfaces for enabling the detection of Potentially Unwanted Applications" was presented at the 2016 European Workshop on Usable Security, and our paper The Challenge of Increasing Safe Response of Antivirus Software Users at MEMICS 2015.

Examining certain Denial of Service attacks, where we analyzed the threat of DDoS-for-hire services to low and medium power cloud-based servers or home users, investigating popularity and availability of such services, their payment models, subscription pricing, complexity of the generated attack traffic and performance. Our paper Service in denial – clouds going with the winds was presented at the Network and System Security 2015. Our paper Analyzing traffic features of common standalone DoS attack tools came with a comparative analysis of traffic features of DoS attacks that were generated by state-of-the-art standalone DoS attack tools. We provide a classification of different attack traffic features, including utilized evasion techniques and encountered anomalies. We also proposed a new research direction for the detection of DoS attacks at the source end, based on repeated attack patterns recognition.

Study of biometric authentication systems. A full version of a paper written with Zdenek Riha and presented at the Computer Information Systems and Industrial Management Applications 2010 conference, is available as the technical report FIMU-RS-2010-07. We have a book on biometric authentication (in Czech), where I took care of co-editing (and writing up some) chapters. An older summary paper reviewing major security and usability issues of biometric authentication systems was presented at the Communications and Multimedia Security Conference, summary of trends and visions was presented at the Information Security Summit 2002, and few other papers presented at other conferences. A good summarizing article Toward Reliable User Authentication through Biometrics appeared in IEEE Security & Privacy and an introductory technical report written also with Zdenek Riha is also available.

Infocommunications Journal and Data Security Management (DSM - Czech security journal published quarterly), where I'm member of the journal Editorial Board. (And I shouldn't forget the latter's annual Information Security Summit, the region's prime event in the area of information security.)

My lectures in security/crypto here at the Masaryk University: More information on these courses can be found through the university webpages on my courses, and our centre at FI.

Information for our students inquiring about supervision, support, etc. can be found at this page.

I supervise PhD students Milan Broz, Lukas Nemec, Matus Nemec, Dusan Klinec, Radim Ostadal, Vladimir Sedlacek, Vlasta Stavova, Martin Ukrop, and I had the pleasure to supervise PhD graduates Vit Bukac, Filip Jurnecka, Jan (Honza) Krhovjak, Marek Kumpost, Jiri Kur, Martin Stehlik, Andriy Stetsko, Petr Svenda.

Older stuff:

Just in case you met me during my sabbaticals with Red Hat Czech and CyLab, Carnegie Mellon University in 2017, or in 2011/12 as a Fulbright-Masaryk Visiting Scholar at the Center for Research on Computation and Society (CRCS), Harvard University, or in 2003/04 either as a Visiting Researcher with Microsoft Research Cambridge, or a Visiting Lecturer with University College Dublin, Department of Computer Science, then yes, it is me. :-) And again thanks to all these institutions, their employees, and other visitors at the time for their kind hospitality and/or inspiring discussions.
Vashek Matyas
E-mail: LastName at
Last update: Feb 14, 2018.