Hill cipher modification based on eigenvalues HCM-EE

Abstract

We propose and analyze a new modification of the Hill cipher, HCM-EE, generating dynamic encryption key matrix by exponentiation that is made efficiently with the help of eigenvalues. Security of HCM-EE is provided by the use of a large number of dynamic keys. Experimental results show that HCM-EE is from two to seven times more effective in the encryption quality of RGB bitmap images than Hill cipher and its known modifications in the case of images with large single colour areas, and slightly more effective otherwise. It is two times faster than HCM-H, having the best encryption quality among Hill cipher modifications compared versus HCM-EE. Copyright 2009 ACM.