5,384 research outputs found
Breaking a chaos-based secure communication scheme designed by an improved modulation method
Recently Bu and Wang [Chaos, Solitons & Fractals 19 (2004) 919] proposed a
simple modulation method aiming to improve the security of chaos-based secure
communications against return-map-based attacks. Soon this modulation method
was independently cryptanalyzed by Chee et al. [Chaos, Solitons & Fractals 21
(2004) 1129], Wu et al. [Chaos, Solitons & Fractals 22 (2004) 367], and
\'{A}lvarez et al. [Chaos, Solitons & Fractals, accepted (2004),
arXiv:nlin.CD/0406065] via different attacks. As an enhancement to the Bu-Wang
method, an improving scheme was suggested by Wu et al. by removing the
relationship between the modulating function and the zero-points. The present
paper points out that the improved scheme proposed by Wu et al. is still
insecure against a new attack. Compared with the existing attacks, the proposed
attack is more powerful and can also break the original Bu-Wang scheme.
Furthermore, it is pointed out that the security of the modulation-based
schemes is not so satisfactory from a pure cryptographical point of view. The
synchronization performance of this class of modulation-based schemes is also
discussed.Comment: elsart.cls, 18 pages, 9 figure
Breaking projective chaos synchronization secure communication using filtering and generalized synchronization
This paper describes the security weaknesses of a recently proposed secure
communication method based on chaotic masking using projective synchronization
of two chaotic systems. We show that the system is insecure and how to break it
in two different ways, by high-pass filtering and by generalized
synchronization.Comment: 14 pages, 6 figures, latex forma
Return-Map Cryptanalysis Revisited
As a powerful cryptanalysis tool, the method of return-map attacks can be
used to extract secret messages masked by chaos in secure communication
schemes. Recently, a simple defensive mechanism was presented to enhance the
security of chaotic parameter modulation schemes against return-map attacks.
Two techniques are combined in the proposed defensive mechanism: multistep
parameter modulation and alternative driving of two different transmitter
variables. This paper re-studies the security of this proposed defensive
mechanism against return-map attacks, and points out that the security was much
over-estimated in the original publication for both ciphertext-only attack and
known/chosen-plaintext attacks. It is found that a deterministic relationship
exists between the shape of the return map and the modulated parameter, and
that such a relationship can be used to dramatically enhance return-map attacks
thereby making them quite easy to break the defensive mechanism.Comment: 11 pages, 7 figure
Security analysis of communication system based on the synchronization of different order chaotic systems
This work analyzes the security weakness of a recently proposed communication
method based on chaotic modulation and masking using synchronization of two
chaotic systems with different orders. It is shown that its application to
secure communication is unsafe, because it can be broken in two different ways,
by high-pass filtering and by reduced order system synchronization, without
knowing neither the system parameter values nor the system key.Comment: 12 pages, 6 figures, LaTeX forma
Cryptographic requirements for chaotic secure communications
In recent years, a great amount of secure communications systems based on
chaotic synchronization have been published. Most of the proposed schemes fail
to explain a number of features of fundamental importance to all cryptosystems,
such as key definition, characterization, and generation. As a consequence, the
proposed ciphers are difficult to realize in practice with a reasonable degree
of security. Likewise, they are seldom accompanied by a security analysis.
Thus, it is hard for the reader to have a hint about their security. In this
work we provide a set of guidelines that every new cryptosystems would benefit
from adhering to. The proposed guidelines address these two main gaps, i.e.,
correct key management and security analysis, to help new cryptosystems be
presented in a more rigorous cryptographic way. Also some recommendations are
offered regarding some practical aspects of communications, such as channel
noise, limited bandwith, and attenuation.Comment: 13 pages, 3 figure
Chaos-based communication scheme using proportional and proportional-integral observers
In this paper, we propose a new chaos-based communication scheme using the observers. The novelty lies in the masking procedure that is employed to hide the confidential information using the chaotic oscillator. We use a combination of the addition and inclusion methods to mask the information. The performance of two observers, the proportional observer (P-observer) and the proportional integral observer (PI-observer) is compared that are employed as receivers for the proposed communication scheme. We show that the P-observer is not suitable scheme since it imposes unpractical constraints on the messages to be transmitted. On the other hand, we show that the PI-observer is the better solution because it allows greater flexibility in choosing the gains of the observer and does not impose any unpractical restrictions on the message
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