A major advantage of broadband carriers is that they enhance the robustness of communications channels to interference from narrowband disturbance. This technology is the basis, for example, of spread-spectrum communication methods such as the code division multiple access protocol, which combines highbandwidth digital information with a pseudorandom digital code. The result is a hard-to-interf...

The security of chaos communication system is superior to other digital communication system, because it has characteristics such as non-periodic, wide-band, nonpredictability, easy implementation and sensitive initial condition. Chaos sequences are non – periodic sequences which are sensitive to their initial conditions i.e. spread factor and time delay respectively. If many antennas are appli...

This paper proposes a digital chaotic secure communication by introducing a concept of magnifying glass, which is used to enlarge and observe minor parameter mismatch so as to increase the sensitivity of the system. The encryption method is based on a one-time pad encryption scheme, where the random key sequence is replaced by a chaotic sequence generated via a Chua’s circuit. In our system, we...

Recently the engineering community began to seek the possibly application of chaos. The fact that the cryptographic community had used discrete pseudo-chaotic systems for a long time to generate cipher keys that leads to the initiation of applying chaos to secure communications. This paper presents a schematic design methodology for a fuzzy observer based secure communication of hyper chaotic s...

In this paper, a scheme for chaotic modulation secure communication is proposed based on chaotic synchronization of an improved Lorenz system. For the first time, the intensity limit and stability of the transmitted signal, the characteristics of broadband and the requirements for accuracy of electronic components are presented by Multisim simulation. In addition, some improvements are made on ...

In the last ten years the interest for chaos has increased due to the great resources represented by the dynamical chaotic systems which can be used to assure secure and wide band communications. Also, chaotic systems are widely used to design analog and digital blocks for communication systems. In this paper we present some aspects regarding the hardware implementation of one well-known digita...

Synchronized chaotic systems have recently been applied to the area of secure communications in a variety of ways. At the same time, there have also been significant advances in deciphering messages masked by chaotic signals. It is important, therefore, to explore more secure approaches to using chaos in communication. We show that multiple chaotic systems can be synchronized through a scalar c...

An external-cavity laser (ECL) operating in a chaotic state is usually used in a chaotic optical secure communication system and its feedback length (FL) is often regarded as an additional key. Our analyses show that an eavesdropper's (Eve) laser can synchronize with a transmitter (Alice) without any knowledge of the FL by simply increasing the injection strength. A sequence of a 1 Gbit/s nonre...