516 research outputs found
Applications of tripled chaotic maps in cryptography
Security of information has become a major issue during the last decades. New
algorithms based on chaotic maps were suggested for protection of different
types of multimedia data, especially digital images and videos in this period.
However, many of them fundamentally were flawed by a lack of robustness and
security. For getting higher security and higher complexity, in the current
paper, we introduce a new kind of symmetric key block cipher algorithm that is
based on \emph{tripled chaotic maps}. In this algorithm, the utilization of two
coupling parameters, as well as the increased complexity of the cryptosystem,
make a contribution to the development of cryptosystem with higher security. In
order to increase the security of the proposed algorithm, the size of key space
and the computational complexity of the coupling parameters should be increased
as well. Both the theoretical and experimental results state that the proposed
algorithm has many capabilities such as acceptable speed and complexity in the
algorithm due to the existence of two coupling parameter and high security.
Note that the ciphertext has a flat distribution and has the same size as the
plaintext. Therefore, it is suitable for practical use in secure
communications.Comment: 21 pages, 10 figure
Chosen-plaintext attack of an image encryption scheme based on modified permutation-diffusion structure
Since the first appearance in Fridrich's design, the usage of
permutation-diffusion structure for designing digital image cryptosystem has
been receiving increasing research attention in the field of chaos-based
cryptography. Recently, a novel chaotic Image Cipher using one round Modified
Permutation-Diffusion pattern (ICMPD) was proposed. Unlike traditional
permutation-diffusion structure, the permutation is operated on bit level
instead of pixel level and the diffusion is operated on masked pixels, which
are obtained by carrying out the classical affine cipher, instead of plain
pixels in ICMPD. Following a \textit{divide-and-conquer strategy}, this paper
reports that ICMPD can be compromised by a chosen-plaintext attack efficiently
and the involved data complexity is linear to the size of the plain-image.
Moreover, the relationship between the cryptographic kernel at the diffusion
stage of ICMPD and modulo addition then XORing is explored thoroughly
On the security of a new image encryption scheme based on chaotic map lattices
This paper reports a detailed cryptanalysis of a recently proposed encryption
scheme based on the logistic map. Some problems are emphasized concerning the
key space definition and the implementation of the cryptosystem using
floating-point operations. It is also shown how it is possible to reduce
considerably the key space through a ciphertext-only attack. Moreover, a timing
attack allows the estimation of part of the key due to the existent
relationship between this part of the key and the encryption/decryption time.
As a result, the main features of the cryptosystem do not satisfy the demands
of secure communications. Some hints are offered to improve the cryptosystem
under study according to those requirements.Comment: 8 pages, 8 Figure
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