7,098 research outputs found
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
Cryptanalyzing a discrete-time chaos synchronization secure communication system
This paper describes the security weakness of a recently proposed secure
communication method based on discrete-time chaos synchronization. We show that
the security is compromised even without precise knowledge of the chaotic
system used. We also make many suggestions to improve its security in future
versions.Comment: 11 pages, 3 figures, latex forma
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
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
Security problems with a chaos-based deniable authentication scheme
Recently, a new scheme was proposed for deniable authentication. Its main
originality lied on applying a chaos-based encryption-hash parallel algorithm
and the semi-group property of the Chebyshev chaotic map. Although original and
practicable, its insecurity and inefficiency are shown in this paper, thus
rendering it inadequate for adoption in e-commerce.Comment: 8 pages, 1 figure, latex forma
Cryptanalysis of an Image Encryption Scheme Based on a Compound Chaotic Sequence
Recently, an image encryption scheme based on a compound chaotic sequence was
proposed. In this paper, the security of the scheme is studied and the
following problems are found: (1) a differential chosen-plaintext attack can
break the scheme with only three chosen plain-images; (2) there is a number of
weak keys and some equivalent keys for encryption; (3) the scheme is not
sensitive to the changes of plain-images; and (4) the compound chaotic sequence
does not work as a good random number resource.Comment: 11 pages, 2 figure
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
Breaking a chaos-noise-based secure communication scheme
This paper studies the security of a secure communication scheme based on two
discrete-time intermittently-chaotic systems synchronized via a common random
driving signal. Some security defects of the scheme are revealed: 1) the key
space can be remarkably reduced; 2) the decryption is insensitive to the
mismatch of the secret key; 3) the key-generation process is insecure against
known/chosen-plaintext attacks. The first two defects mean that the scheme is
not secure enough against brute-force attacks, and the third one means that an
attacker can easily break the cryptosystem by approximately estimating the
secret key once he has a chance to access a fragment of the generated
keystream. Yet it remains to be clarified if intermittent chaos could be used
for designing secure chaotic cryptosystems.Comment: RevTeX4, 11 pages, 15 figure
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