Slovak University of Technology, Bratislava
Faculty of Informatics and Information Technologies
Degree Course: INFORMATICS
Author: Bc. Alfréd Radler
Diploma thesis: Design and cryptographic evaluation of one variation of Hill's cipher
Supervisor: Prof. RNDr. Otokar Groek, PhD.
This thesis deals with design and testing of the block ciphers based on mixing of substitutions and linear transformations. Linear transformation is realized by multiplication by the matrix in finite field GF(216). In the thesis there were designed and implemented two different structures of the round of such a cipher. The Iterated Hill cipher with nonlinear word substitution and the Feistel-like cipher using this variant of the Hill cipher as a round function were tested. Properties of these ciphers for different number of iterations were analyzed and tested.
The result of the thesis is the design of the structure and parameters of the cipher that demonstrated sufficient security level during testing. Advantages and disadvantages of the practical usage of such a cipher were evaluated.