887 research outputs found
Fast, parallel and secure cryptography algorithm using Lorenz's attractor
A novel cryptography method based on the Lorenz's attractor chaotic system is
presented. The proposed algorithm is secure and fast, making it practical for
general use. We introduce the chaotic operation mode, which provides an
interaction among the password, message and a chaotic system. It ensures that
the algorithm yields a secure codification, even if the nature of the chaotic
system is known. The algorithm has been implemented in two versions: one
sequential and slow and the other, parallel and fast. Our algorithm assures the
integrity of the ciphertext (we know if it has been altered, which is not
assured by traditional algorithms) and consequently its authenticity. Numerical
experiments are presented, discussed and show the behavior of the method in
terms of security and performance. The fast version of the algorithm has a
performance comparable to AES, a popular cryptography program used commercially
nowadays, but it is more secure, which makes it immediately suitable for
general purpose cryptography applications. An internet page has been set up,
which enables the readers to test the algorithm and also to try to break into
the cipher in
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
Synchronization of spatiotemporal semiconductor lasers and its application in color image encryption
Optical chaos is a topic of current research characterized by
high-dimensional nonlinearity which is attributed to the delay-induced
dynamics, high bandwidth and easy modular implementation of optical feedback.
In light of these facts, which adds enough confusion and diffusion properties
for secure communications, we explore the synchronization phenomena in
spatiotemporal semiconductor laser systems. The novel system is used in a
two-phase colored image encryption process. The high-dimensional chaotic
attractor generated by the system produces a completely randomized chaotic time
series, which is ideal in the secure encoding of messages. The scheme thus
illustrated is a two-phase encryption method, which provides sufficiently high
confusion and diffusion properties of chaotic cryptosystem employed with unique
data sets of processed chaotic sequences. In this novel method of cryptography,
the chaotic phase masks are represented as images using the chaotic sequences
as the elements of the image. The scheme drastically permutes the positions of
the picture elements. The next additional layer of security further alters the
statistical information of the original image to a great extent along the
three-color planes. The intermediate results during encryption demonstrate the
infeasibility for an unauthorized user to decipher the cipher image. Exhaustive
statistical tests conducted validate that the scheme is robust against noise
and resistant to common attacks due to the double shield of encryption and the
infinite dimensionality of the relevant system of partial differential
equations.Comment: 20 pages, 11 figures; Article in press, Optics Communications (2011
Chaos Based Cryptography An Alternative to Algebraic Cryptography
In this paper we will first discuss cryptography
from a historical point of view in order to
understand the motivation behind this science. We
will discuss the earliest form of cryptography
before fast forwarding to the current modem forms
of cryptography.
We will then mention issues surrounding current
modem cryptographic methods before introducing
chaos based cryptography. The relationship
between chaos and cryptography makes it natural
to employ chaotic systems to design new
cryptosystems. It is based on the facts that chaotic
signals are usually noise-like and chaotic systems
are very sensitive to initial conditions. Their
sensitivity to initial conditions and their spreading
out of trajectories over the whole interval seems to
be a model that satisfies the classic Shannon
requirements of confusion and diffusion [1] From 1989 onwards, many different chaotic
encryption systems have been proposed. The most
celebrated chaotic cryptosystem is based on the
ergodicity property of chaotic maps [2] and has
received more and more attentions in the past
literature [3-17]. Introduced by Baptista in 1998, it
is able to produce different ciphers for the same
plaintext.
It was cracked by Alvarez in 2003 via the one-time
pad attack. In 2008, M.R.K.Ariffin and
M.S.M.Noorani [22] engaged the attack and
devised a counter measure against it
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