Secure communication protocols with discrete nonlinear chaotic maps

The discrete nonlinear chaotic maps (DNCMs) exploit a novel approach to enc ryption: the information is injected to a properly designed DNCM system and affects its dynamics. The evolution of a proper variable of this system co mposes the transmitted ciphertext. Consequently, this variable controls the dynamics of another DNCM system that acts as the decipher. The paper proposes two new secure communications protocols that utilise the peculiarities of the DNCM systems. At the first one, the DNCM systems are used to construct a unique authentication scheme. With the second protocol the participants instead of exchanging the symmetric key (encrypted with th e public key) 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 des ign rules). (C) 2001 Elsevier Science B.V. All rights reserved.