Jiri Dvorský

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In this article we discuss a simple hash function based upon properties of a well-known combinatorial design called quasigroups. The quasigroups are equivalent to the more familiar Latin squares and one of their most important properties is that all possible element of certain quasigroup occurs with equal probability. Actual implementations are based on(More)
In this article we present a new compression method, called WLZW, which is a word-based modiication of classic LZW. The modiication is similar to the approach used in the HuuWord compression algorithm. The algorithm is two-phase, the compression ratio achieved is fairly good, on average 22%-20% (see 2, 3]). Moreover, the table of words, which is side(More)
—In this study we discuss a method for evolution of quasigroups with desired properties based on genetic algorithms. Quasigroups are a well-known combinatorial design equivalent to the more familiar Latin squares. One of their most important properties is that all possible elements of certain quasigroup occur with equal probability. The quasigroups are(More)
The paper is oriented to the problem of clustering for large datasets with high-dimensions. We propose a two-phase combined method with regard to high dimensions and exploiting the standard clustering algorithm. The first step of the method is based on the learning phase using artificial neural network, especially Self organizing map, which we find as a(More)
Non-associative quasigroups are well known combinatorial designs with many different applications. Many cryptographic algorithms based on quasigroups primitives have been published. There are several classifications of quasigroups based on their algebraic properties. In this paper we propose a new classification of quasigroups based upon strings (product(More)
—With the growing importance of data security a growing effort to find new approaches to the cryptographic algorithms designs appears. One of the trends is to research the use of other algebraic structures than the traditional, such as a quasigroup. Quasigroups are equivalent to the more familiar Latin squares. There are many characteristics that must(More)
Quasigroups are a well-known combinatorial design equivalent to more familiar Latin squares. Because all possible elements of a quasigroup occur with equal probability, it makes it an interesting tool for the application in computer security and for production of pseudo-random sequences. Prior implementations of quasigroups were based on look-up table of(More)
Quasigroups are a well-known combinatorial design equivalent to more familiar Latin squares. Because all possible elements of a quasigroup occur with equal probability, it makes it an interesting tool for the application in computer security and for production of pseudo-random sequences. Most implementations of quasigroups are based on look-up table of the(More)