TECHNIQUE OF THE TESTING OF PSEUDORANDOM SEQUENCES

The article is dedicated to systematization of scientific positions about the static testing of sequences, widely used in cryptographic systems of information protection for the production of key and additional information (random numbers, vectors of initialization, etc.). Existing approaches to testing pseudorandom sequences, their advantages and disadvantages are considered. It is revealed that for sequences of length up to 100 bits there are not enough existing statistical packets. Perspective direction of research – static testing of sequences using n- dimensional statistics is considered. The joint distributions of 2-chains and 3-chains of a fixed type of random (0, 1) -sequences allow for statistical analysis of local sections of this sequence. Examples, tables, diagrams that can be used to test for randomness of the location of zeros and ones in the bit section are 16 lengths. The paper proposes a methodology for testing pseudorandom sequences, an explicit form of the joint distribution of 2- and 3-chains numbers of various options of random bit sequence of a given small length is obtained. As a result of the implementation of this technique, an information system will be created that will allow analyzing the pseudorandom sequence of a small length and choosing a quality pseudorandom sequence for use in a particular subject area.

Towards Understanding the Formation of Uniform Local Binary Patterns

The research reported in this paper focuses on the modeling of Local Binary Patterns (LBPs) and presents an a priori model where LBPs are considered as combinations of permutations. The aim is to increase the understanding of the mechanisms related to the formation of uniform LBPs. Uniform patterns are known to exhibit high discriminative capability; however, so far the reasons for this have not been fully explored. We report an observation that although the overall a priori probability of uniform LBPs is high, it is mostly due to the high probability of only certain classes of patterns, while the a priori probability of other patterns is very low. In order to examine this behavior, the relationship between the runs up and down test for randomness of permutations and the uniform LBPs was studied. Quantitative experiments were then carried out to show that the relative effect of uniform patterns to the LBP histogram is strengthened with deterministic data, in comparison with the i.i.d. model. This was verified by using an a priori model as well as through experiments with natural image data. It was further illustrated that specific uniform LBP codes can also provide responses to salient shapes, that is, to monotonically changing intensity functions and edges within the image microstructure.