Industrial Automatic Control Systems and Controllers Annotation << Back Modular Checking Algorithm Statistically Indistinguishable Filter Functions Representable as a Sum of Two Functions of Disjoint Variables Rozhkov M.I., Obrosov P.A In this paper we propose a new algorithm for verifying statistical indistinguishability (regarding probabilities of output s-grams) of sequences generated by functions f:Xn→F2 in the law gi = f(xi,xi+1,…,xi+n-1), i =1,2,… In this initial sequence x1,x2,… is viewed as a sequence of independent identically distributed random variables defined on the input alphabet X and takes values x∈X with probability px>0, ∑px=1. This algorithm identifies the indistinguishability of the output for a given pair f,j functions of 2n variables, which are represented by the sum of two functions of n disjoint variables The proposed algorithm uses modular operations on integers of standard length and has a much lower computational complexity compared to the previously known algorithm applied to the functions of the general form of 2n variables. The results may be useful in the construction and justification of the statistical properties of random sequences using the appropriate complicating conversion of intermediate scales. Keywords: statistical indistinguishability; statistical equivalence; filtering function; Boolean functions; m-grams; cryptography. Contacts: E-mail: rozhkov.m.i@yandex.ru, E-mail: mobelus@mail.ru Pp. 20-26.