2016. 1st Issue
Full issue (10,7MB)
Václav (Vashek) Matyáš, Zdeněk Říha and Pavol Zajac
Special Issue on Applied Cryptography
PAPERS OF THE SPECIAL ISSUE
Karel Kubíček, Jiří Novotný, Petr Švenda and Martin Ukrop
New results on reduced-round Tiny Encryption Algorithm using genetic programming
Analysis of cryptoprimitives usually requires extensive work of a skilled cryptanalyst. Some automation is possible, e.g. by using randomness testing batteries such as Statistical Test Suite from NIST (NIST STS) or Dieharder. Such batteries compare the statistical properties of the function's output stream to the theoretical values. A potential drawback is a limitation to predefined tested patterns. However, there is a new approach – EACirc is a genetically inspired randomness testing framework based on finding a dynamically constructed test. This test works as a probabilistic distinguisher separating cipher outputs from truly random data.
In this work, we use EACirc to analyze the outputs of Tiny Encryption Algorithm (TEA). TEA was selected as a frequently used "benchmark" algorithm for cryptanalytic approaches based on genetic algorithms. In this paper, we provide results of EACirc applied to TEA ciphertext created from differently structured plaintext. We compare the methodology and results with previous approaches for limited-round TEA. A different construction of EACirc tests also allows us to determine which part of cipher's output is relevant to the decision of a well-performing randomness distinguisher.
Side Channels in SW Implementation of the McEliece PKC
The McEliece cryptosystem is considered secure in the presence of quantum computers because there is no known quantum algorithm to solve the problem this cryptosystem is built on. However, naive implementation of the cryptosystem can open side channels, which can be used to gather information about the message or the secret key. In this paper we present results of chosen timing attacks on straightforward implementation of this cryptosystem. Furthermore, we present practical countermeasures and evaluate their efficacy.
Romana Linkeová and Pavel Příhoda
Cryptanalysis based on the theory of symmetric group representations
The key exchange Diffie-Hellman protocol originally works over the group Z*p where p is at least a 300-digit number. Even though this implementation is simple and secure, it makes the protocol unsuitable for devices with limited computational power. This fact led to a research of other algebraic structures which could be used as a platform for this protocol in order to decrease the computational and storage costs. Such attempt can be found in the work of D. Kahrobaei et al. posted in 2013. D. Kahrobaei et al. proposed a structure of small matrices over a group ring as a platform and claimed that this modification will not affect the security of the Diffie-Hellman protocol. We will attack this modification and prove that it is not secure with the help of the theory of symmetric group representations.
PAPERS FROM OPEN CALL
Norbert Bátfai, Péter Jeszenszky, András Mamenyák, Béla Halász, Renátó Besenczi, János Komzsik, Balázs Kóti, Gergely Kövér, Máté Smajda, Csaba Székelyhídi, Tamás Takács, Géza Róka and Márton Ispány
Competitive Programming: a Case Study for Developing a Simulation-based Decision Support System
FootballAvatar is an experimental industrial research and development subproject of the project 'SziMe3D–3D technological innovation in tourism, education and sport'. FootballAvatar aims to produce a novel decision support information system based on simulations for professional football clubs. This paper establishes the notion of football avatar in the sense of information technology, though it has a strong mathematical background. However, we would like to apply it in several analytic and simulation software tools developed in our project. The main question is that how this notion could be implemented and used in several software environments including C++, Java, and R, or from an architectural viewpoint, on desktops, smart phones, and tablets, while the kinds of uses and the base definitions have often changed during the R&D phases. This changing of the precise interpretation of the notion of "football avatar" has a direct impact on selecting the software process model. For this reason, we have developed an own software methodology called Competitive Programming (CP), which will be presented in detail, as the main result of the present paper. Our main goal with CP was to create a methodology that allows us to work effectively even when the objectives to achieve are changing rapidly. As an example of the application of the methodology, the paper discusses the aforementioned FootballAvatar project.
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