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Shumen, Bulgaria

The Constantine of Preslav University of Shumen in Bulgaria is named after one of the most well-educated and talented students of Saints Cyril and Methodius, Constantine of Preslav. He was a writer, a religious figure and a significant person in Old Bulgarian culture. Wikipedia.

Stoyanov B.P.,University of Shumen
AIP Conference Proceedings

We propose a new cryptographic scheme based on the Lorenz chaos attractor and 32 bit bent Boolean function. We evaluated the keystream generated by the scheme with batteries of the NIST statistical tests. We also applied a number of statistical analysis techniques, such as calculating histograms, correlations between two adjacent pixels, information entropy, and differential resistance, all refer to images encrypted by the proposed system. The results of the analysis show that the new cryptographic scheme ensures a secure way for sending digital data with potential applications in real-time image encryption. © 2012 American Institute of Physics. Source

Dimitrov D.P.,Bulgarian Academy of Science | Kjurkchieva D.P.,University of Shumen
Monthly Notices of the Royal Astronomical Society

CCD photometric observations in VRI colours and spectroscopic observations of the newly discovered eclipsing binary GSC 2314-0530 (NSVS 6550671) with dMe components and a very short period of P = 0.192 636 d are presented. The simultaneous light-curve solution and radial velocity solution allow us to determine the global parameters of GSC 2314-0530: T1 = 3735 K; T2 = 3106 K; pc. The chromospheric activity of its components is revealed by strong emission in the Hα line (with mean EW = 5 Å) and several observed flares. Empirical relations for mass-, mass-radius and mass-temperature are derived on the basis of the parameters of known binaries with low-mass dM components. © 2010 The Authors. Journal compilation © 2010 RAS. Source

Yankov N.,University of Shumen
IEEE Transactions on Information Theory

In this paper, we prove that there does not exist a binary self-dual doubly even $[72, 36, 16]$ code with an automorphism of order 9. To do so, we apply a method for constructing binary self-dual codes possessing an automorphism of order $p2$ for an odd prime $p$. © 2006 IEEE. Source

Stoyanov B.,University of Shumen
Advanced Studies in Theoretical Physics

In this paper, we design a self-shrinking scheme which combines a feedback with carry shift register and the self-shrinking generator, based on A. Kanso PhD study. We calculated the period of the designed algorithm. The key gamma is statistically tested with NIST test suite. The result of the analysis shows that the properties of the output bits are like randomly generated physical phenomena. © 2014 Borislav Stoyanov. Source

Stoyanov B.P.,University of Shumen
AIP Conference Proceedings

In this paper, we study a pseudo-random bit generator based on two Chebyshev polynomial maps. The novel derivative algorithm shows perfect statistical properties established by number of statistical tests. © 2013 AIP Publishing LLC. Source

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