Abstract. A5/1 pseudo-random bit generator, known from GSM networks, potentially might be used for different purposes, such as secret hiding during cryptographic hardware testing, stream encryption in piconets and others. The main advantages of A5/1 are low cost and a fixed output ratio. We show that a hardware implementation of A5/1 and similar constructions must be quite careful. It faces a danger of a new kind of attack, which significantly reduces possible keyspace, allowing full recovery of A5/1 internal registers' content. We use "fault analysis" strategy: we disturb the A5/1 encrypting device (namely, clocking of the LFSR registers) so it produces an incorrect keystream, and through error analysis we deduce the state of the internal registers. If a secret material is used to initialize the generator, like in GSM, this may enable recovering the secret. The attack is based on unique properties of the clocking scheme used by A5/1, which is the basic security component of this construction. The computations that have to be performed in our attack are about 100 times faster than in the cases of the previous fault-less cryptanalysis methods.

Abstract. We present two efficient and simple fault attacks on the shrinking generator. In a first case if the attacker can stop control generator for some small number of steps and observe the output, then with high probability he can deduce the full control sequence, and so the other input bitstream. The second method assumes that the attacker can disturb the control sequence (in an unpredictable and random way) and observe many samples of such experiments. Then he can reconstruct a certain sequence that agrees with the input sequence of the generator on a large fraction of bits.

An original method for analyzing the influence of the meteorological, as well as physical-geographical conditions on the flooding of stormwater in small urban catchment areas is proposed. A logistical regression model is employed for the identification of the flooding events. The elaborated model enables to simulate the stormwater flooding in a single rainfall event, on the basis of the rainfall depth, duration, imperviousness of the catchment and its spatial distribution within the analyzed area, as well as the density of the stormwater network. The rainfall events are predicted considering the regional convective rainfall model for 32 rain gauges located in Poland, based on 44 years of rainfall data. In the study, empirical models are obtained to calculate the rainfall duration conditioning the flooding of stormwater in a small urban catchment area depending on the characteristics of the examined urban basins. The empirical models enabling to control the urbanization process of catchment areas, accounting for the local rainfall and meteorological characteristics are provided. The paper proposes a methodology for the identification of the areas especially sensitive to stormwater flooding in small urban catchment areas depending to the country scale. By employing the presented methodology, the regions with most sensitive urban catchments are identified. On this basis, a ranking of towns and cities is determined from the most sensitive to flooding in small urban catchment areas to the regions where the risk of flooding is lower. Using the method developed in the paper, maximum impervious catchment area are determined for the selected regions of the country, the exceedance of which determines the occurrence of stormwater flooding.

No abstract

The growing demand for energy is accelerating the process of consuming non-renewable energy sources, so special attention should be paid to the development of renewable energy as the energy obtained from renewable energy sources (RES) will reduce the consumption of primary raw materials and reduce emissions of harmful substances entering the atmosphere. The aim of this article is thus to investigate the attitude of Polish consumers towards renewable energy sources and to discover the relationship between the level of awareness and other factors such as age and education. The results of the research revealed that there was a correlation between the age and level of education of the respondents and their willingness to consider the issues related to renewable energy sources and implement solutions in their households that take into account the consumption of natural energy sources (p-value of the significance test for age is 0.0001227, and p-values of independence test for the level of education are 0.00013). The discovery of such correlations will allow knowing in which direction the efforts should be intensified in order to reach the largest part of society.