Performance analysis of Jakimoski-Kocarev attack on a class of chaotic cryptosystems

Recently Jakimoski and Kocarev cryptanalyzed two chaotic cryptosystems without using chaotic synchronization - Baptista cryptosystem and Alvarez cryptosystem. As a result, they pointed out that neither of the two cryptosystems are secure to known-plaintext attacks. In this Letter, we re-study the performance of Jakimoski-Kocarev attack on Baptista cryptosystem and find that it is not efficient enough as a practical attack tool. Furthermore, a simple but effective remedy is presented to resist Jakimoski-Kocarev attack, and the detailed discussion on its performance are given.