On Multiple Symmetric Fixed Points in GOST

Abstract

In this article the author revisits the oldest attack on GOST known, the Kara Reflection attack, and another totally unrelated truncated differential attack by Courtois and Misztal. It is hard to imagine that there could be any relationship between two so remote attacks which have nothing in common. However, there is one: Very surprisingly, both properties can be combined and lead the fastest attack on GOST ever found, which is nearly feasible to execute in practice.