One Modification of the Alternating Step Generator

Report published in the Proceedings of the National Conference on "Education and Research in the Information Society", Plovdiv, May, 2019In this paper, we propose a research on the modified alternating step generator implementation based on feedback with carry shift registers. The scheme is proposed by Schneier. We calculated the period of the derivative algorithm. The key gamma is statistically tested with NIST test suite. The result of the analysis shows that the output data are such a random physical phenomena generated.Association for the Development of the Information Society, Institute of Mathematics and Informatics Bulgarian Academy of Sciences, Plovdiv University "Paisii Hilendarski

Yet Another Pseudorandom Number Generator

We propose a novel pseudorandom number generator based on R\"ossler attractor and bent Boolean function. We estimated the output bits properties by number of statistical tests. The results of the cryptanalysis show that the new pseudorandom number generation scheme provides a high level of data security.Comment: 5 pages, 7 figures; to be published in International Journal of Electronics and Telecommunications, vol.63, no.

Least Significant Bit Steganography using Hitzl-Zele Chaotic Map

We propose a novel least significant bit steganography algorithm based on a Hitzl-Zele chaotic function. Exact study has been provided on the novel scheme using visual inspection, peak signal-to-noise ratio, and histogram analysis. The experimental data show excellent performance of the novel stego technique

N-adic Summation-Shrinking Generator. Basic properties and empirical evidences.

The need of software-flexible stream ciphers has led to several alternative proposals in the last few years. One of them is a new Pseudo Random Number Generator (PRNG), named N-adic Summation-Shrinking (NSumSG), which architecture is described in this paper. It uses N-1 parallel working slave summation generators and one N-adic summation generator, controlling the nonlinearity in the generator. The implementation, some properties and statistical tests of NSumSG are given. The results from statistical analysis show that the sequence generated by NSumSG is uniform, scalable, uncompressible, whit large period; consistent and unpredictable. This gives the reason consider the NSumSG as suitable for a particular cryptographic application

SHAH: Hash Function based on Irregularly Decimated Chaotic Map

In this paper, we propose a novel hash function based on irregularly decimated chaotic map. The hash function called SHAH is based on two Tinkerbell maps filtered with irregular decimation rule. Exact study has been provided on the novel scheme using distribution analysis, sensitivity analysis, static analysis of diffusion and confusion, and collision analysis. The experimental data show that SHAH satisfied admirable level of security.Comment: accepted for publication in International Journal of Electronics and Telecommunications, vol. 6

Web Based Information System for Heat Supply Monitoring

The paper presents web based information system for heat supply monitoring. The proposed model  and information system for gathering data from heating station heat-flow meters and regulators is software realized. The novel system with proved functionality can be commercialized at the cost of minimal investments, finding wildly use on Bulgarian market as cheap and quality alternative of the western systems

A Novel Pseudorandom Bit Generator Based on Chirikov Standard Map Filtered with Shrinking Rule

This communication proposes a simplified model of pseudorandom bit generator, based on two Chirikov standard maps filtered with shrinking rule. The study also demonstrates that the generated keystreams have excellent properties of randomness and resistance to statistical attacks, which is proven by using the NIST, ENT, and DIEHARD testing suites

For optical flickering in symbiotic star MWC 560

This study is based on observations of MWC560 during the last two observational seasons (2020/2021 and 2021/2022). Other than looking for flickering we were interested in following the variability of brightness in the same period. Looking for similarities in the spectra with other types of stars is also of great interest to us because it could help clarify the stellar configuration of such objects. Our observations during the last two observational seasons of MWC560 confirm the absence of flickering. From the similarities of the gathered spectra of XX Oph and MWC560 we assume that the components in XX Oph are a red giant and a white dwarf, which are also surrounded by a common shell

First survey on the invasive Pond slider (Trachemys scripta) in Bulgaria: historic development and current situation

Crvenouha kornjača (Trachemys scripta) postala je popularni ljubimac u Bugarskoj od 1990. Kroz godine sve veći broj jedinki zabilježen je i u divljini. Iako su negativni učinci na izvornim kornjače su opsežno studirao negdje drugdje, nema posebne studije (osim kratkih izvješća) obratili invaziju T. scripta u Bugarskoj. Ova studija se temelji na više od 25 godina praćenja na terenu i predstavlja prvi izvor detaljne informacije o raspodjeli Pond klizača u Bugarskoj. Ukupno 293 UTM (10 × 10 km) kvadrata sa staništa pogodna za slatkovodne kornjače ispitano. Prikupili smo 64 zapisa za 173 osoba, od 19 UTM kvadrata. Od svih promatranih osoba, samo dvije su od nominirati podvrste - ostatak pripada T. Š. elegans. U našem istraživanju je uočeno samo jednoga djeteta. Do danas nije uspješno leženja zabilježena, iako su registrirani uspješni overwinterings. Mi smo razgovarali o raznim mjere ublažavanja koje se moraju brzo pokrenut ograničiti buduće izdanje Ribnjak klizača i za uklanjanje ne-izvornih uzoraka s bugarskim ekosustava. Akcije su zahtijevali posebno da se izbjegne potencijalne epidemiološko događaja uzrokovanih parazitima s vrlo smrtonosnim učinkom na autohtonim vrstama. Takve pojave potencijalno mogu imati veći utjecaj na autohtone vrste kornjača jezerce od raznih oblika natjecanja s T. scripta.Pond sliders (Trachemys scripta) have become a popular pet in Bulgaria since 1990. Through the years a number of released specimens were observed in the wild. Although the negative effects on native turtles have been studied extensively elsewhere, no specific studies (besides brief reports) have addressed the invasion of T. scripta in Bulgaria. The present study is based on over 25 years of field monitoring and represents the first source of detailed information on the distribution of the Pond slider in Bulgaria. A total of 293 UTM (10×10 km) squares with habitats suitable for freshwater turtles were surveyed. We collected 64 records for 173 individuals, from 19 UTM squares. From all observed individuals, only two were from the nominate subspecies – the rest belong to T. s. elegans. In our study only one subadult was observed. To date no successful hatching has been recorded, although successful overwinterings have been registered. We discuss various mitigation measures that must be rapidly initiated to limit future release of Pond sliders and to remove the non-native specimens from the Bulgarian ecosystems. Actions are demanded especially to avoid the potential epizootic events caused by parasites with highly lethal effect on native species. Such outbreaks might potentially have greater impact on the native pond turtle species than various forms of competition with T. scripta