286 research outputs found
Image Encryption using AES Encryption Technique with Bernoulli Chaotic Map
In last few years, the progress in communication technology has seen strong interest in digital picture or image transmission. However, computer processor growth in possessing power and storage illegal access has become easier. Encryption method involves some special mathematical algorithms and keys to transform digital data into cipher text or code before they are transmitted and decrypted method involves the application of mathematical algorithms and keys to obtain the original data from cipher text or code, scientific community have seen strong interest in image transmission. However, illegal image or data access has become more easy and established in wireless and general communication networks. Information privacy becomes a difficult issue. In order to protect, secure your valuable image or data from unauthorized readers, data or image encryption or decryption is essential, furthermore. As such in this paper, AES based on encryption has been proposed for secure image transmission over channels
Deterministic Chaos in Digital Cryptography
This thesis studies the application of deterministic chaos to digital
cryptography. Cryptographic systems such as pseudo-random generators
(PRNG), block ciphers and hash functions are regarded as a dynamic
system (X, j), where X is a state space (Le. message space)
and f : X -+ X is an iterated function. In both chaos theory and
cryptography, the object of study is a dynamic system that performs
an iterative nonlinear transformation of information in an apparently
unpredictable but deterministic manner. In terms of chaos theory, the
sensitivity to the initial conditions together with the mixing property
ensures cryptographic confusion (statistical independence) and diffusion
(uniform propagation of plaintext and key randomness into cihertext).
This synergetic relationship between the properties of chaotic and
cryptographic systems is considered at both the theoretical and practical
levels: The theoretical background upon which this relationship is
based, includes discussions on chaos, ergodicity, complexity, randomness,
unpredictability and entropy.
Two approaches to the finite-state implementation of chaotic systems
(Le. pseudo-chaos) are considered: (i) floating-point approximation of
continuous-state chaos; (ii) binary pseudo-chaos. An overview is given
of chaotic systems underpinning cryptographic algorithms along with
their strengths and weaknesses. Though all conventional cryposystems
are considered binary pseudo-chaos, neither chaos, nor pseudo-chaos are
sufficient to guarantee cryptographic strength and security.
A dynamic system is said to have an analytical solution Xn = (xo)
if any trajectory point Xn can be computed directly from the initial
conditions Xo, without performing n iterations. A chaotic system with an
analytical solution may have a unpredictable multi-valued map Xn+l =
f(xn). Their floating-point approximation is studied in the context of
pseudo-random generators.
A cryptographic software system E-Larm ā¢ implementing a multistream
pseudo-chaotic generator is described. Several pseudo-chaotic
systems including the logistic map, sine map, tangent- and logarithm feedback
maps, sawteeth and tent maps are evaluated by means of floating point
computations. Two types of partitioning are used to extract
pseudo-random from the floating-point state variable: (i) combining the
last significant bits of the floating-point number (for nonlinear maps);
and (ii) threshold partitioning (for piecewise linear maps). Multi-round
iterations are produced to decrease the bit dependence and increase non-linearity.
Relationships between pseudo-chaotic systems are introduced
to avoid short cycles (each system influences periodically the states of
other systems used in the encryption session).
An evaluation of cryptographic properties of E-Larm is given using
graphical plots such as state distributions, phase-space portraits, spectral
density Fourier transform, approximated entropy (APEN), cycle length
histogram, as well as a variety of statistical tests from the National Institute
of Standards and Technology (NIST) suite. Though E-Larm passes
all tests recommended by NIST, an approach based on the floating-point
approximation of chaos is inefficient in terms of the quality/performance
ratio (compared with existing PRNG algorithms). Also no solution is
known to control short cycles.
In conclusion, the role of chaos theory in cryptography is identified;
disadvantages of floating-point pseudo-chaos are emphasized although
binary pseudo-chaos is considered useful for cryptographic applications.Durand Technology Limite
On the Eigenstructures of Functional K-Potent Matrices and Their Integral Forms
In this paper, a functional k-potent matrix satisfies the equation, where k and r are positive integers, and are real numbers. This class of matrices includes idempotent, Nilpotent, and involutary matrices, and more. It turns out that the matrices in this group are best distinguished by their associated eigen-structures. The spectral properties of the matrices are exploited to construct integral k-potent matrices, which have special roles in digital image encryption
A Differential Cryptanalysis of Yen-Chen-Wu Multimedia Cryptography System (MCS)
At ISCAS'2005, Yen et al. presented a new chaos-based cryptosystem for
multimedia transmission named "Multimedia Cryptography System" (MCS). No
cryptanalytic results have been reported so far. This paper presents a
differential attack to break MCS, which requires only seven chosen plaintexts.
The complexity of the attack is O(N), where is the size of plaintext.
Experimental results are also given to show the real performance of the
proposed attack.Comment: 22 pages, 5 figure
Entropy in Dynamic Systems
In order to measure and quantify the complex behavior of real-world systems, either novel mathematical approaches or modifications of classical ones are required to precisely predict, monitor, and control complicated chaotic and stochastic processes. Though the term of entropy comes from Greek and emphasizes its analogy to energy, today, it has wandered to different branches of pure and applied sciences and is understood in a rather rough way, with emphasis placed on the transition from regular to chaotic states, stochastic and deterministic disorder, and uniform and non-uniform distribution or decay of diversity. This collection of papers addresses the notion of entropy in a very broad sense. The presented manuscripts follow from different branches of mathematical/physical sciences, natural/social sciences, and engineering-oriented sciences with emphasis placed on the complexity of dynamical systems. Topics like timing chaos and spatiotemporal chaos, bifurcation, synchronization and anti-synchronization, stability, lumped mass and continuous mechanical systems modeling, novel nonlinear phenomena, and resonances are discussed
A Novel Color Image Encryption Scheme Based on Arnoldās Cat Map and 16-Byte S-box
The presented work sets out to subsidize to the general body of knowledge in the field of cryptography application by evolving color image encryption and decryption scheme based on the amalgamation of pixel shuffling and efficient substitution. Arnoldās cat map is applied to snap off the correlation in pixels of image and the shuffled image is encrypted by 16-byte S-box substitution. Computer simulations with a standard test image and the outcome is presented to scrutinize the competence of the projected system. Several image-quality measures and security analyses have been made out for the encrypted image to estimate the statistical and differential strength of the scheme. A comparison is presented by following out the scheme with 256-byte S-box and 16-nibble S-box to support for sturdiness of the idea. It is concluded from the results of analyses that the proposed scheme with 16-byte S-box can resist exhaustive attacks and is apt for practical applications
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