Cryptography, Delayed Dynamical Systems, and Secure Communication

Abstract

The idea of using synchronized chaotic circuits for sending and receiving signals when they are masked using classical cryptography is extended to the case of delayed dynamical systems. It is observed that due to the existence of the delayed parameter t, the mode of communication is more secure due to the fact that the delayed parameter is changed at a fixed interval by both the sender and receiver. It is shown how an extended set of secret keys could be constructed to send a message containing both numerical and alphabetical sequences. Again, a secure communication scheme is also discussed based on the synchronization of two coupled delayed dynamical systems with a varying coupling parameter.