Protocols for secure communications with discrete nonlinear chaotic maps

The paper exploits the application of Discrete Nonlinear Chaotic Maps (DNCMs) for the effective encryption of information. The DNCMs exploit a different approach to encryption from the traditional one: The information is injected to a properly designed DNCM system and affects its dynamics. The ciphertext is consisted from the evolution of a proper variable of this system and it controls the dynamics of another DNCM system that acts as the decipher. Two new secure communications protocols are proposed: At the first one, the DNCM systems are used to construct a novel digital signature scheme. With the second protocol the participants instead of exchanging the symmetric key (encrypted with the public key) they exchange the encryption components themselves. This protocol is well suited to the possibility for dynamic "randomized" construction of DNCM systems. Therefore, a new dimension to security is added: not only the symmetric encryption key of a communication session is randomized but also the encryption algorithm itself is generated randomly (subject to some design rules).