An attack on Dömösi's cryptosystem
Zita Kovács, Andor Pénzes · University of Debrecen Electronic Archive (University of Debrecen) · 2012
In this paper we introduce an attack on a practical stream cipher based on a finite automata without outputs. For encryption and decryption the apparatus uses the same secret keys, which have the transition matrix of a key-automaton without outputs and with an initial state and final states. This cryptosystem called Domosi cryptosystem from its maker. First, we introduce the system without its restrictions and we introduce the attack, which is based on probability theorem and create equivalent classes. The result of the attack an automaton which is state-equivalent to the key -automaton of the cryptosystem. Then we show the restrictions which help us against the attack.