“…In this paper we mainly focus on papers (Sakalauskas et al, 2008;Mihalkovich and Sakalauskas, 2012;Sakalauskas et al, 2017) and (Liu et al, 2016). In the latter paper authors present an attack based on linear algebra, which can be applied to protocols, presented in Sakalauskas et al (2008) and Mihalkovich and Sakalauskas (2012) to break them in polynomial time. Our aim is to prove that the latest version of the so-called matrix power asymmetric cipher (MPAC), presented in Sakalauskas et al (2017), is resistant to the declared attack, thus repairing the flaw found.…”