I.S. Vershinin

Researches described in the article are generalization of the works on two-dimensional-associative masking mechanism used in the protection of cartographical objects. This background information is represented as a set of stegocontainers placed in a distributed geographic information systems. Experiment-s results give answer for the next two questions: 1. Is it possible with the knowledge of a gamma section, used at randomization, to generate a correct set of masks used by an authorized user for the masking? 2. What is the time complexity of the experimental definition of the correct gamma using pseudorandom sequence generator «Mersenne twister»? As a solution of the first problem is developed the algorithm 1. Implementation of the given algorithm for a case of thirty three stegocontainers affirmatively allows to answer the first question. The question of the principle possibility of finding a correct gamma section used in the randomization is solved by using technique, by which is implemented a search procedure using «windows», allocated by shift of 1 bit from some initial state of the pseudorandom sequence generator. Concluded the impossibility of viewing all «windows» in a reasonable time. Earlier researches and researches described in this article on the method of associative stegoprotection can be attributed to a provably resistant methods