6,837 research outputs found
Mirror Theory and Cryptography
``Mirror Theory\u27\u27 is the theory that evaluates the number of
solutions of affine systems of equalities (=) and non equalities () in finite groups.
It is deeply related to the security and attacks of many generic cryptographic
secret key schemes, for example random Feistel schemes (balanced or unbalanced), Misty
schemes, Xor of two pseudo-random bijections to generate a pseudo-random
function etc. In this paper we will assume that the groups are abelian. Most of
time in cryptography the group is and we
will concentrate this paper on these cases. We will present here general definitions, some theorems, and many examples and computer simulations
Post Quantum Cryptography from Mutant Prime Knots
By resorting to basic features of topological knot theory we propose a
(classical) cryptographic protocol based on the `difficulty' of decomposing
complex knots generated as connected sums of prime knots and their mutants. The
scheme combines an asymmetric public key protocol with symmetric private ones
and is intrinsecally secure against quantum eavesdropper attacks.Comment: 14 pages, 5 figure
Quantum Cryptography
Quantum cryptography could well be the first application of quantum mechanics
at the individual quanta level. The very fast progress in both theory and
experiments over the recent years are reviewed, with emphasis on open questions
and technological issues.Comment: 55 pages, 32 figures; to appear in Reviews of Modern Physic
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
Fast and User-friendly Quantum Key Distribution
Some guidelines for the comparison of different quantum key distribution
experiments are proposed. An improved 'plug & play' interferometric system
allowing fast key exchange is then introduced. Self-alignment and compensation
of birefringence remain. Original electronics implementing the BB84 protocol
and allowing user-friendly operation is presented. Key creation with 0.1 photon
per pulse at a rate of 486 Hz with a 5.4% QBER - corresponding to a net rate of
210Hz - over a 23 Km installed cable was performed.Comment: 21 pages, 6 figures, added referenc
Rapid Generation of Light Beams Carrying Orbital Angular Momentum
We report a technique for encoding both amplitude and phase variations onto a
laser beam using a single digital micro-mirror device (DMD). Using this
technique, we generate Laguerre-Gaussian and vortex orbital-angular-momentum
(OAM) modes, along with modes in a set that is mutually unbiased with respect
to the OAM basis. Additionally, we have demonstrated rapid switching among the
generated modes at a speed of 4 kHz, which is much faster than the speed
regularly achieved by spatial light modulators (SLMs). The dynamic control of
both phase and amplitude of a laser beam is an enabling technology for
classical communication and quantum key distribution (QKD) systems that employ
spatial mode encoding
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