Algorithm for simplifying the SHA-256 operations tree

Abstract

- The article offers an algorithm for simplification of Boolean operations tree, which is obtained as a result of analyzing the execution of the SHA-256 hash function. The main idea of the algorithm is that we can reduce the size of the tree by replacing non-optimal Boolean subexpressions with smaller ones. This algorithm can later be used for cryptanalysis of the JSON Web Token protocol as an auxiliary tool that can simplify the search for the key. As a result, we will show that such operations trees can be significantly reduced with offered algorithm.