10-08-2012, 12:43 PM
CHAOS COMMUNICATION
[attachment=30926]
Introduction
Chaos communications is an application of chaos theory
which is aimed to provide security in the transmission of
information performed through telecommunications technologies.
By secure communications, one has to understand that
the contents of the message transmitted are inaccessible to
possible eavesdroppers.In chaos communications security (i.e.,
privacy) is based on the complex dynamic behaviors provided
by chaotic systems. Some properties of chaotic dynamics, such
as complex behaviour, noise-like dynamics (pseudorandom
noise) and spread spectrum, are used to encode data. On the
other hand, being chaos a deterministic phenomenon, it is
possible to decode data using this determinism. In practice,
implementations of chaos communications devices resort to
one of two chaotic phenomena: synchronization of chaos, or
control of chaos.To implement chaos communications using
such properties of chaos, two chaotic oscillators are required
as a transmitter (or master) and receiver (or slave). At the
transmitter, a message is added on to a chaotic signal and then,
the message is masked in the chaotic signal. As it carries the
information, the chaotic signal is also called chaotic carrier.
Synchronizing of these oscillators is similar to synchronizing
random neural nets in neural cryptography.
The definition of Chaos
There is no universally agreed definition of chaos. However,
most people would accept the following working definition:
Chaos is aperiodic time-asymptotic behaviour in a deterministic
system which exhibitssensitive dependence on initial
conditions. This definition contains three main elements:
1) 1. Aperiodic time-asymptotic behaviour -This implies
the existence of phase-space trajectories which do not
settle down to fixed points or periodic orbits. For practical
reasons, we insist that these trajectories are not too
rare. We also require the trajectories to be bounded.
Systems involve in Chaotic communication
All systems can be basically divided into three types:
1) a. Deterministic systems: These are systems for which
for a given set of conditions the result can be predicted
and the output does not vary much with change in initial
condition
2) b. Stochastic systems: These systems, which are not
as reliable as deterministic systems.Their output can be
predicted only for a certain range of values
3) c. Chaotic systems:Chaotic systems are the most unpredictable
of the three systems.Moreover they are very
sensitive to initial conditions and a small change in
initial conditions can bring about a great change in its
output.
Conclusion
A very brief overview on Chaotic Communication has
been described, explaining the system setup of synchronised
chaotic communication chaotic and direct communication with
comparison to traditional communication system setup. A few
of the main chaotic modulating schemes have been described.
The majority of the research carried out sofar proves that
chaotic communication system has quite a number of advantages
over traditional communication. Every technology has
its own advantages and disadvantages. We also had an over
view of history of chaotic secure communications.
[attachment=30926]
Introduction
Chaos communications is an application of chaos theory
which is aimed to provide security in the transmission of
information performed through telecommunications technologies.
By secure communications, one has to understand that
the contents of the message transmitted are inaccessible to
possible eavesdroppers.In chaos communications security (i.e.,
privacy) is based on the complex dynamic behaviors provided
by chaotic systems. Some properties of chaotic dynamics, such
as complex behaviour, noise-like dynamics (pseudorandom
noise) and spread spectrum, are used to encode data. On the
other hand, being chaos a deterministic phenomenon, it is
possible to decode data using this determinism. In practice,
implementations of chaos communications devices resort to
one of two chaotic phenomena: synchronization of chaos, or
control of chaos.To implement chaos communications using
such properties of chaos, two chaotic oscillators are required
as a transmitter (or master) and receiver (or slave). At the
transmitter, a message is added on to a chaotic signal and then,
the message is masked in the chaotic signal. As it carries the
information, the chaotic signal is also called chaotic carrier.
Synchronizing of these oscillators is similar to synchronizing
random neural nets in neural cryptography.
The definition of Chaos
There is no universally agreed definition of chaos. However,
most people would accept the following working definition:
Chaos is aperiodic time-asymptotic behaviour in a deterministic
system which exhibitssensitive dependence on initial
conditions. This definition contains three main elements:
1) 1. Aperiodic time-asymptotic behaviour -This implies
the existence of phase-space trajectories which do not
settle down to fixed points or periodic orbits. For practical
reasons, we insist that these trajectories are not too
rare. We also require the trajectories to be bounded.
Systems involve in Chaotic communication
All systems can be basically divided into three types:
1) a. Deterministic systems: These are systems for which
for a given set of conditions the result can be predicted
and the output does not vary much with change in initial
condition
2) b. Stochastic systems: These systems, which are not
as reliable as deterministic systems.Their output can be
predicted only for a certain range of values
3) c. Chaotic systems:Chaotic systems are the most unpredictable
of the three systems.Moreover they are very
sensitive to initial conditions and a small change in
initial conditions can bring about a great change in its
output.
Conclusion
A very brief overview on Chaotic Communication has
been described, explaining the system setup of synchronised
chaotic communication chaotic and direct communication with
comparison to traditional communication system setup. A few
of the main chaotic modulating schemes have been described.
The majority of the research carried out sofar proves that
chaotic communication system has quite a number of advantages
over traditional communication. Every technology has
its own advantages and disadvantages. We also had an over
view of history of chaotic secure communications.