On the application of wide-trail strategy to improve an extended feistel cryptosystem

In this paper, we discuss a wide-trail-strategy-based method able to enhance the security offered by an encryption scheme developed in the University of Ferrara and based on an extended Feistel structure. By adding a new diffusion layer to the basic round transformation of the original system, we are able to increase the amount of active transformations, improving both the strength of the scheme against linear and differential attacks and the whole cipher performance by considerably reducing the system decoding time.