Out of Non-linearity: Search Impossible Differentials by the Bitwise Characteristic Matrix

2021 ◽  
pp. 69-89
Author(s):  
Yunxiao Yang ◽  
Xuan Shen ◽  
Bing Sun
Keyword(s):  
Characteristic Matrix ◽  
Impossible Differentials

scholarly journals A New Automatic Tool Searching for Impossible Differential of NIST Candidate ACE

Mathematics ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1576
Author(s):  
Jingyi Liu ◽  
Guoqiang Liu ◽  
Longjiang Qu
Keyword(s):  
Characteristic Matrix ◽  
Differential Attack ◽  
Optimal Permutation ◽  
The Usa ◽  
Standardization Process ◽  
Impossible Differential ◽  
Automatic Tool ◽  
Ace Algorithm ◽  
Impossible Differentials ◽  
Impossible Differential Cryptanalysis

The ACE algorithm is a candidate of the Lightweight Cryptography standardization process started by the National Institute of Standards and Technology (NIST) of the USA that passed the first round and successfully entered the second round. It is designed to achieve a balance between hardware cost and software efficiency for both authenticated encryption with associated data (AEAD) and hashing functionalities. This paper focuses on the impossible differential attack against the ACE permutation, which is the core component of the ACE algorithm. Based on the method of characteristic matrix, we build an automatic searching algorithm that can be used to search for structural impossible differentials and give the optimal permutation for ACE permutation and other SPN ciphers. We prove that there is no impossible differential of ACE permutation longer than 9 steps and construct two 8-step impossible differentials. In the end, we give the optimal word permutation against impossible differential cryptanalysis, which is π′=(2,4,1,0,3), and a safer word XOR structure of ACE permutation.

scholarly journals Improved Impossible Differentials and Zero-Correlation Linear Hulls of New Structure III

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jun He ◽  
Xuan Shen ◽  
Guoqiang Liu
Keyword(s):  
Block Cipher ◽  
Characteristic Matrix ◽  
Linear Cryptanalysis ◽  
The Core ◽  
Round Function ◽  
Linear Layer ◽  
Zero Correlation ◽  
Impossible Differential ◽  
Impossible Differentials ◽  
Impossible Differential Cryptanalysis

Impossible differential cryptanalysis and zero-correlation linear cryptanalysis are two kinds of most effective tools for evaluating the security of block ciphers. In those attacks, the core step is to construct a distinguisher as long as possible. In this paper, we focus on the security of New Structure III, which is a kind of block cipher structure with excellent resistance against differential and linear attacks. While the best previous result can only exploit one-round linear layer P to construct impossible differential and zero-correlation linear distinguishers, we try to exploit more rounds to find longer distinguishers. Combining the Miss-in-the-Middle strategy and the characteristic matrix method proposed at EUROCRYPT 2016, we could construct 23-round impossible differentials and zero-correlation linear hulls when the linear layer P satisfies some restricted conditions. To our knowledge, both of them are 1 round longer than the best previous works concerning the two cryptanalytical methods. Furthermore, to show the effectiveness of our distinguishers, the linear layer of the round function is specified to the permutation matrix of block cipher SKINNY which was proposed at CRYPTO 2016. Our results indicate that New Structure III has weaker resistance against impossible differential and zero-correlation linear attacks, though it possesses good differential and linear properties.

Model and Method for Contributor’s Quality Assessment in Community Image Tagging Systems

2018 ◽  
pp. 45-51
Author(s):  
A. V. Ponomarev
Keyword(s):  
Large Scale ◽  
Wide Spectrum ◽  
Preference Relation ◽  
Pairwise Comparison ◽  
Ground Truth ◽  
Comparison Method ◽  
Characteristic Matrix ◽  
Image Tagging ◽  
Proposed Model

Introduction: Large-scale human-computer systems involving people of various skills and motivation into the information processing process are currently used in a wide spectrum of applications. An acute problem in such systems is assessing the expected quality of each contributor; for example, in order to penalize incompetent or inaccurate ones and to promote diligent ones.Purpose: To develop a method of assessing the expected contributor’s quality in community tagging systems. This method should only use generally unreliable and incomplete information provided by contributors (with ground truth tags unknown).Results:A mathematical model is proposed for community image tagging (including the model of a contributor), along with a method of assessing the expected contributor’s quality. The method is based on comparing tag sets provided by different contributors for the same images, being a modification of pairwise comparison method with preference relation replaced by a special domination characteristic. Expected contributors’ quality is evaluated as a positive eigenvector of a pairwise domination characteristic matrix. Community tagging simulation has confirmed that the proposed method allows you to adequately estimate the expected quality of community tagging system contributors (provided that the contributors' behavior fits the proposed model).Practical relevance: The obtained results can be used in the development of systems based on coordinated efforts of community (primarily, community tagging systems). 

DESIGN AND IMPLEMENTATION OF WIRELESS MULTI-CHANNEL EEG RECORDING SYSTEM AND STUDY OF EEG CLUSTERING METHOD

2006 ◽  
Vol 18 (06) ◽  
pp. 276-283 ◽  
Author(s):  
ROBERT LIN ◽  
REN-GUEY LEE ◽  
CHWAN-LU TSENG ◽  
YAN-FA WU ◽  
JOE-AIR JIANG
Keyword(s):  
Energy Operator ◽  
Digital Processing ◽  
Recording System ◽  
Ar Model ◽  
Characteristic Matrix ◽  
Eeg Signal ◽  
Eeg Signals ◽  
Long Distance ◽  
Communication Module ◽  
Processing Circuit

A multi-channel wireless EEG (electroencephalogram) acquisition and recording system is developed in this work. The system includes an EEG sensing and transmission unit and a digital processing circuit. The former is composed of pre-amplifiers, filters, and gain amplifiers. The kernel of the later digital processing circuit is a micro-controller unit (MCU, TI-MSP430), which is utilized to convert the EEG signals into digital signals and fulfill the digital filtering. By means of Bluetooth communication module, the digitized signals are sent to the back-end such as PC or PDA. Thus, the patient's EEG signal can be observed and stored without any long cables such that the analogue distortion caused by long distance transmission can be reduced significantly. Furthermore, an integrated classification method, consisting of non-linear energy operator (NLEO), autoregressive (AR) model, and bisecting k-means algorithm, is also proposed to perform EEG off-line clustering at the back-end. First, the NLEO algorithm is utilized to divide the EEG signals into many small signal segments according to the features of the amplitude and frequency of EEG signals. The AR model is then applied to extract two characteristic values, i.e., frequency and amplitude (peak to peak value), of each segment and to form characteristic matrix for each segment of EEG signal. Finally, the improved modified k-means algorithm is utilized to assort similar EEG segments into better data classification, which allows accessing the long-term EEG signals more quickly.

Effect of Double Defects on Transmission Spectra of One-Dimensional Photonic Crystals

2010 ◽  
Vol 663-665 ◽  
pp. 725-728 ◽  
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai ◽  
Yun Gao Cai
Keyword(s):  
Photonic Crystals ◽  
Band Gap ◽  
Theoretical Calculations ◽  
Stop Band ◽  
Band Gaps ◽  
Characteristic Matrix ◽  
Frequency Range ◽  
Defect Band ◽  
One Dimensional ◽  
The One

Considered the model of the one-dimensional photonic crystals (1-D PCs) with double defects, the refractive indexes (n2’, n3’ and n2’’, n3’’) of the double defects were 2.0, 4.0 and 4.0, 2.0 respectively. With parameter n2=1.5, n3=2.5, by theoretical calculations with characteristic matrix method, the results shown that for a certain number (14 was taken) of layers of the 1-D PCs, when the double defects abutted, there was a defect band gap in the stop band gap, while when the double defects separated, there occurred two defect band gaps in the stop band gap; besides, with the separation of the two defects, the transmittance of the double defect band gaps decreased gradually. In addition, in this progress, the frequency range of the stop band gap has a little increase from 0.092 to 0.095.

Free Vibration of Orthotropic Skew Plates

1999 ◽  
Vol 122 (3) ◽  
pp. 313-317 ◽  
Author(s):  
A. M. Farag ◽  
A. S. Ashour
Keyword(s):  
Boundary Conditions ◽  
Transition Matrix ◽  
Longitudinal Direction ◽  
Displacement Function ◽  
Characteristic Matrix ◽  
Skew Angle ◽  
Kantorovich Method ◽  
Vibration Effect ◽  
Finite Strip Method ◽  
Semianalytical Method

The main purpose of this paper is to develop a fast converging semianalytical method for assessing the vibration effect on thin orthotropic skew (or parallelogram/oblique) plates. Since the geometry of the skew plate is not helpful in the mathematical treatments, the analysis is often performed by more complicated and laborious methods. A successive conjunction of the Kantorovich method and the transition matrix is exploited herein to develop a new modification of the finite strip method to reduce the complexity of the problem. The displacement function is expressed as the product of a basic trigonometric series function in the longitudinal direction and an unknown function that has to be determined in the other direction. Using the new transition matrix, after necessary simplification and the satisfaction of the boundary conditions, yields a set of simultaneous equations that leads to the characteristic matrix of vibration. The influence of the skew angle, the aspect ratio, the properties of orthotropy, and the prescribed boundary conditions are investigated. Convergence of the solution is investigated and the accuracy of the results is compared with that available from other numerical methods. The numerical results show that the convergence is rapidly deduced and the comparisons agree very well with known results. [S0739-3717(00)00202-6]

REFRACTIVE INDEX PROFILE RECONSTRUCTION OF PLANAR WAVEGUIDE FROM ITS MODE INTENSITY USING CHARACTERISTIC MATRIX METHOD

2001 ◽  
Vol 10 (02) ◽  
pp. 169-179
Author(s):  
HENRI P. URANUS ◽  
M. O. TJIA
Keyword(s):  
Refractive Index ◽  
Intensity Distribution ◽  
Planar Waveguide ◽  
Nonlinear Least Squares ◽  
Refractive Index Profile ◽  
Characteristic Matrix ◽  
Least Squares Regression ◽  
Index Profile ◽  
Measured Intensity ◽  
Parameter Values

A method is proposed for the reconstruction of refractive index profile of planar waveguide from its fundamental mode intensity profile. The reconstruction is performed by fitting the calculated intensity distribution iteratively with the measured intensity distribution employing nonlinear least-squares regression technique. At each stage of iteration, new trial parameter values are generated and used to form a waveguide model approximated by a multilayer structure with stepwise index distribution, upon which the intensity distribution is then calculated by using the characteristic matrix technique. This method was numerically examined by using samples of either known or unknown analytic expression of the index profile.

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