Observer-based chaos synchronization in the generalized chaotic Lorenz systems and its application to secure encryption

This paper studies the application of the observer-based chaos synchronization in the so-called Generalized Lorenz systems to secure encryption. More precisely, a modified version of the Chaos Shift Keying (CSK) scheme for secure encryption and decryption of data is proposed. Recall, that the classical CSK method determines the correct value of binary signal through checking which unsynchronized system is getting synchronized. On the contrary, our novel method, called as the Anti-Synchronization Chaos Shift Keying (ACSK) method, determines wrong value of binary signal through checking which already synchronized system is loosing synchronization. Even when using two very close each to other chaotic systems, the anti-synchronization is thousand times faster than synchronization. As a consequence, unlike the classical CSK, the method proposed here requires very reasonable amount of data to encrypt and time to decrypt a single bit. Moreover, its security can be systematically investigated showing its good resistance against typical decryption attacks.