LEADER 00000nam 2200373 4500
001 AAINQ77124
005 20050908073016.5
008 050908s2002 eng d
020 0612771245
035 (UnM)AAINQ77124
040 UnM|cUnM
100 1 Yao, Weiguang
245 10 Improving security communication via chaotic
synchronization
300 147 p
500 Source: Dissertation Abstracts International, Volume: 64-
02, Section: B, page: 0758
500 Advisers: Chris Essex; Pei Yu
502 Thesis (Ph.D.)--The University of Western Ontario (Canada),
2002
520 Chaos produces a random-like wideband signal sensitive to
initial conditions. When a chaotic signal is used as a
"carrier" to send a message, the message is not only
carried, but also "masked" by the carrier. The message may
be recovered perfectly at a receiver that is synchronized
with the transmitter by using the received signal. This
method, called chaotic encryption, is an alternative way
for secure communication
520 Some cracking methods, however, have been designed to show
that such a communication may not be secure enough if the
transmitter carrier is generated by simple forms of chaos.
One way for improving the security of chaotic encryption
is to construct a chaotic system which generates more
complicated signals. Another way is to design chaotic
synchronization approaches to increase the randomness of
the carrier even if the carrier is from a less complicated
chaotic system
520 A chaotic synchronization approach is designed. Here, two
identical chaotic systems can be synchronized by long
interval impulsive chaotic signals. The recovered message
is error-free even though a little large noise is added
into the systems. The security of the communication is
much higher than that using continuous chaotic signals
because the randomness of the carrier is greatly increased
and it is very difficult to reconstruct an attractor from
the carrier
520 A generalized competitive mode (GCM) approach is
developed. The idea of the approach is that chaos is the
result of a form of mode competition. The necessary
condition for a system to be chaotic is that there are at
least two such GCM's in the system. By using the necessary
condition, the chaotic parameter regimes in several
chaotic systems are estimated. Further, it is found that
the number and the form of GCM's will affect the
complexity of chaos. Therefore, one can construct new
chaotic systems with pre-designed GCM's. Several new
chaotic systems are created. Some iii of them produce very
complex chaotic motions. The nonlinear dynamical
forecasting (NDF) technique, perhaps the most complicated
and powerful cracking method, is employed to show that the
security of the communication via these systems is much
improved compared to some well-known chaotic systems. Thus,
the work may make it possible to develop devices for
reasonably secure and practical communication in industry.
(Abstract shortened by UMI.)
590 School code: 0784
590 DDC
650 4 Mathematics
650 4 Engineering, Electronics and Electrical
690 0405
690 0544
710 20 The University of Western Ontario (Canada)
773 0 |tDissertation Abstracts International|g64-02B
856 40 |uhttp://pqdd.sinica.edu.tw/twdaoapp/servlet/
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