7,860 research outputs found
The dynamics of the CBC Mode of Operation
In cryptography, the Cipher Block Chaining (CBC), one of the most commonly
used mode in recent years, is a mode of operation that uses a block cipher to
provide confidentiality or authenticity. In our previous research work, we have
shown that this mode of operation exhibits, under some conditions, a chaotic
behaviour. We have studied this behaviour by evaluating both its level of
sensibility and expansivity. In this paper, we intend to deepen the topological
study of the CBC mode of operation and evaluate its property of topological
mixing. Additionally, other quantitative evaluations are performed, and the
level of topological entropy has been evaluated too.Comment: Nonlinearity, IOP Publishing, 2016. arXiv admin note: text overlap
with arXiv:1601.0813
A dynamical systems approach to the discrimination of the modes of operation of cryptographic systems
Evidence of signatures associated with cryptographic modes of operation is
established. Motivated by some analogies between cryptographic and dynamical
systems, in particular with chaos theory, we propose an algorithm based on
Lyapunov exponents of discrete dynamical systems to estimate the divergence
among ciphertexts as the encryption algorithm is applied iteratively. The
results allow to distinguish among six modes of operation, namely ECB, CBC,
OFB, CFB, CTR and PCBC using DES, IDEA, TEA and XTEA block ciphers of 64 bits,
as well as AES, RC6, Twofish, Seed, Serpent and Camellia block ciphers of 128
bits. Furthermore, the proposed methodology enables a classification of modes
of operation of cryptographic systems according to their strength.Comment: 14 pages, 10 figure
Quantitative Evaluation of Chaotic CBC Mode of Operation
The cipher block chaining (CBC) block cipher mode of operation presents a
very popular way of encrypting which is used in various applications. In
previous research work, we have mathematically proven that, under some
conditions, this mode of operation can admit a chaotic behavior according to
Devaney. Proving that CBC mode is chaotic is only the beginning of the study of
its security. The next step, which is the purpose of this paper, is to develop
the quantitative study of the chaotic CBC mode of operation by evaluating the
level of sensibility and expansivity for this mode.Comment: in International Conference on Advanced Technologies for Signal &
Images Processing ATSIP'2016 , Mar 2016, Monastir, Tunisi
Hydrodynamic response of rotationally supported flows in the Small Shearing Box model
The hydrodynamic response of the inviscid small shearing box model of a
midplane section of a rotationally supported astrophysical disk is examined. An
energy functional is formulated for the general nonlinear problem.
It is found that the fate of disturbances is related to the conservation of
this quantity which, in turn, depends on the boundary conditions utilized:
is conserved for channel boundary conditions while it is not
conserved in general for shearing box conditions. Linearized disturbances
subject to channel boundary conditions have normal-modes described by Bessel
Functions and are qualitatively governed by a quantity which is a
measure of the ratio between the azimuthal and vertical wavelengths. Inertial
oscillations ensue if - otherwise disturbances must in general be
treated as an initial value problem. We reflect upon these results and offer a
speculation.Comment: 6 pages, resubmitted to Astronomy and Astrophysics, shortened with
references adde
Symmetry-protected dissipative preparation of matrix product states
We propose and analyze a method for efficient dissipative preparation of
matrix product states that exploits their symmetry properties. Specifically, we
construct an explicit protocol that makes use of driven-dissipative dynamics to
prepare the Affleck-Kennedy-Lieb-Tasaki (AKLT) states, which features
symmetry-protected topological order and non-trivial edge excitations. We show
that the use of symmetry allows for robust experimental implementation without
fine-tuned control parameters. Numerical simulations show that the preparation
time scales polynomially in system size . Furthermore, we demonstrate that
this scaling can be improved to by using parallel
preparation of AKLT segments and fusing them via quantum feedback. A concrete
scheme using excitation of trapped neutral atoms into Rydberg state via
Electromagnetically Induced Transparency is proposed, and generalizations to a
broader class of matrix product states are discussed
Proving chaotic behaviour of CBC mode of operation
International audienceThe cipher block chaining (CBC) block cipher mode of operation was invented by IBM (International Business Machine) in 1976. It presents a very popular way of encrypting which is used in various applications. In this paper, we have mathematically proven that, under some conditions, the CBC mode of operation can admit a chaotic behaviour according to Devaney. Some cases will be properly studied in order to put in evidence this idea
Accessibility dynamics and regional cross-border cooperation (CBC) perspectives in the portuguese—spanish borderland
Accessibility plays a major role in achieving sustainable transport, and therefore urban
and regional sustainability. The urban public transport system promotes mobility and realizes a
large part of urban movements. Moreover, improving accessibility in order to promote sustainable
transport requires the application of new concepts and indicators as a powerful tool in the process of
creating a balanced urban transport system. In this regard, one of the main goals of this research
is to present an overview of the relevant accessibility indicators and assessment of accessibility in
regional Cross-Border Cooperation (CBC) in order to transcendence challenges and obstacles for
sustainable transportation in these regions along of Portuguese-Spanish border. This paper focuses
on the accessibility of cross-border cooperation scenarios along the border regions of Alto Alentejo
(Portugal) and Badajoz (Spain) where the Case Study Research Method (CSR) made it possible to
recognize accessibility as a key factor in territorial success. Also, accessibility analysis can assess
improvements as well as regional imbalances. In addition, this methodology can be used to identify
missing links, which requires new investments enabling long-term sustainability.info:eu-repo/semantics/publishedVersio
Gravitational waves: search results, data analysis and parameter estimation
The Amaldi 10 Parallel Session C2 on gravitational wave (GW) search results, data analysis and parameter estimation included three lively sessions of lectures by 13 presenters, and 34 posters. The talks and posters covered a huge range of material, including results and analysis techniques for ground-based GW detectors, targeting anticipated signals from different astrophysical sources: compact binary inspiral, merger and ringdown; GW bursts from intermediate mass binary black hole mergers, cosmic string cusps, core-collapse supernovae, and other unmodeled sources; continuous waves from spinning neutron stars; and a stochastic GW background. There was considerable emphasis on Bayesian techniques for estimating the parameters of coalescing compact binary systems from the gravitational waveforms extracted from the data from the advanced detector network. This included methods to distinguish deviations of the signals from what is expected in the context of General Relativity
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