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SQUARE attack on block ciphers with low algebraic degree

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Science china(information sciences) 2010年第10期53卷 1988-1995页

作者： SUN Bing 1 , LI RuiLin 1 , QU LongJiang 1,3 & LI Chao 1,2,3 1 Science College of National university of Defense Technology, Changsha 410073, china 2.state key laboratory of information security, graduate university of chinese academy of sciences, beijing 100049, china 3 National Mobile Communications Research laboratory, Southeast university, Nanjing 210096, china Science College of National university of Defense Technology Changsha China National Mobile Communications Research laboratory Southeast University Nanjing China state key laboratory of information security Graduate University of Chinese Academy of Sciences Beijing China

By using an algebraic method, the mathematical foundation of SQUARE attack is studied in this paper. We point out that a SQUARE distinguisher exists if and only if the degree of the polynomial function between n-bit input which is active and n-bit output which is balanced is 2 n-2. And the algebraic method can also be used to determine the property of a balanced set after passed through a nonlinear S-box, by which in some cases we can find a SQUARE distinguisher with more rounds. The validity of SQUARE attack and the influence of the choice of S-box are also studied. If the round function of a Feistel cipher has a low algebraic degree, a SQUARE attack cannot recover the right keys in some special cases. However, SQUARE attack on SPN ciphers always holds. The relations among SQUARE attack and some other cryptanalytic method are studied, showing that if a cipher is breakable by SQUARE attack, then it is also breakable by the interpolation attack.

关键词： SQUARE attack interpolation attack integral attack block cipher

A revision of Elaeagnus L. (Elaeagnaceae) in china's mainland

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Journal of Systematics and Evolution 2010年第5期48卷 356-390页

作者： 1,2 Miao SUN 1Qi LIN 1(state key laboratory of Systematic and Evolutionary Botany,Institute of Botany,chinese academy of sciences,beijing 100093,china) 2(graduate university of chinese academy of sciences,beijing 100049,china)

A revision of Elaeagnus *** china’s mainland is provided based on field observations and herbarium ***-two morphological characters are selected and coded,then the matrix is prepared following cluster *** characters and species delimitation are re-evaluated resulting in the recognition of 36 species,one subspecies and five varieties in china’s *** species names and three variety names are regarded as new *** information covers full synonyms,type information,description,taxonomic remarks,distribution range,occupied habitats,examined specimens,relevant illustrations,and references to selected published illustrations and reports.A key for whole species determination is *** lectotypification of Elaeagnus magna(Serv.)*** been designated.

关键词： cluster analysis Elaeagnaceae Elaeagnus relationships synonymy taxonomic revision.

Studies and advances on joint source-channel encoding/decoding techniques in flow media communications

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Science china(information sciences) 2010年第1期53卷 1-17页

作者： TU GuoFang1, LIU JianJun1, ZHANG Can1,2, GAO ShaoShuai3 & LI ShiDong4 1School of information Science and Engineering, graduate university of chinese academy of sciences, beijing 100049, china 2state key laboratory of information security, graduate university of chinese academy of sciences, beijing 100049, china 3National Institute of Standards and Technology, Gaithersburg, MD 20899, USA, 4Department of Mathematics, San Francisco state university, San Francisco, CA 94132, USA School of information Science and Engineering Graduate University of Chinese Academy of Sciences Beijing China state key laboratory of information security Graduate University of Chinese Academy of Sciences Beijing China National Institute of Standards and Technology Gaithersburg USA Department of Mathematics San Francisco State University San Francisco USA

Joint source-channel coding/decoding (JSCC/JSCD) techniques in flow media communications have become a state-of-the-art and one of the challenging research subjects in the spatial communication area. They have great application prospective and deep impact in various manned space flights, satellite missions, mobile radio communications and deep-space explorations. In the last few years, there have been influential achievements in JSCC/JSCD studies. This paper aims at an introduction to the basic principles of joint source-channel optimal design. A general summarization and classification for various existing JSCC/JSCD methods is addressed. Also presented is a JSCD scheme based on variable-length coding, capable of providing reliable resolutions for flow media data transmission in spatial communications.

关键词： joint source-channel coding/decoding rate allocation variable-length coding/decoding iterative decoding

SOME RESULTS ON GENERALIZED DIFFERENCE SETS

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Journal of Systems Science & Complexity 2008年第1期21卷 76-84页

作者： Xiwang CAO School of Mathematical Science, Nanjing university of Aeronautics and Astronautics, Nanjing 210016, china state key Lab. of information security, beijing 100049, china. School of Mathematical Science Nanjing University of Aeronautics and Astronautics Nanjing China state key Lab. of information security China

Sequences with ideal correlation functions have important applications in communications such as CDMA, FDMA, etc. It has been shown that difference sets can be used to construct such sequences. The author extends Pott and Bradley＇s method to a much broader case by proposing the concept of generalized difference sets. Some necessary conditions for the existence of generalized difference sets are established by means of some Diophantine equations. The author also provides an algorithm to determine the existence of generalized difference sets in the cyclic group Zv. Some examples are presented to illustrate that our method works.

关键词： Correlation functions diophantine equations generalized difference sets.

Perceptual video hashing robust against geometric distortions

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Science china(information sciences) 2012年第7期55卷 1520-1527页

作者： XIANG ShiJun 1,4 ,YANG JianQuan 2 & HUANG JiWu 3 1 School of information Science and Technology,Jinan university,Guangzhou 510632,china 2 Shenzhen Institutes of Advanced Technology,chinese academy of sciences,Shenzhen 518055,china 3 School of information Science and Technology,Sun Yat-sen university,Guangzhou 510275,china 4 state key laboratory of information security,Institute of Software,chinese academy of sciences,beijing 100049,china School of information Science and Technology Jinan University Guangzhou China state key laboratory of information security Institute of Software Chinese Academy of Sciences Beijing China Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen China School of information Science and Technology Sun Yat-sen University Guangzhou China

In this paper,we propose a robust perceptual hashing algorithm by using video luminance histogram in *** underlying robustness principles are based on three main aspects:1) Since the histogram is independent of position of a pixel,the algorithm is resistant to geometric deformations; 2) the hash is extracted from the spatial Gaussian-filtering low-frequency component for those common video processing operations such as noise corruption,low-pass filtering,lossy compression,etc.; 3) a temporal Gaussian-filtering operation is designed so that the hash is resistant to temporal desynchronization operations,such as frame rate change and *** a result,the hash function is robust to common geometric distortions and video processing *** results show that the proposed hashing strategy can provide satisfactory robustness and uniqueness.

关键词： video hashing geometric distortion histogram Gaussian filtering

Modeling of Hillslope Runoff and Soil Erosion at Rainfall Events Using Cellular Automata Approach

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Pedosphere 2009年第6期19卷 711-718页

作者： MA Ting ZHOU Cheng-Hu CAI Qiang-Guo state key laboratory of Resources and Environmental information System Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 (China) graduate university of the chinese academy of sciences Beijing 100049 (China)

A novel quantitative cellular automata (CA) model that simulates and predicts hillslope runoff and soil erosion caused by rainfall events was developed by integrating the local interaction rules and the hillslope surface hydraulic processes. In this CA model, the hillslope surface was subdivided into a series of discrete spatial cells with the same geometric features. At each time step, water and sediment were transported between two adjacent spatial cells. The flow direction was determined by a combination of water surface slope and stochastic assignment. The amounts of interchanged water and sediment were computed using the Chezy-Manning formula and the empirical sediment transport equation. The water and sediment discharged from the open boundary cells were considered as the runoff and the sediment yields over the entire hillslope surface. Two hillslope soil erosion experiments under simulated rainfall events were carried out. Cumulative runoff and sediment yields were measured, respectively. Then, the CA model was applied to simulate the water and soil erosion for these two experiments. Analysis of simulation results indicated that the size of the spatial cell, hydraulic parameters, and the setting of time step and iteration times had a large impact on the model accuracy. The comparison of the simulated and measured data suggested that the CA model was an applicable alternate for simulating the hillslope water flow and soil erosion.

关键词： hillslope surface hydraulic parameters sediment simulation water

Weight hierarchies of linear codes satisfying the Near-Chain condition

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Progress in Natural Science:Materials International 2005年第9期15卷 784-792页

作者： LIU Zihui1** and CHEN Wende2(1. School of Mathematical sciences, Peking university, beijing 100871, china 2. laboratory of Systems and Control and key state laboratory of information security, Institute of Systems Science, academy of Mathematics and Systems Science, chinese academy of sciences, beijing 100080, china) School of Mathematical sciences Peking University Beijing 100871 China laboratory of Systems and Control and key state laboratory of information security Institute of Systems Science Academy of Mathematics and Systems Sciences Chinese Academy of Sciences Beijing 100080 China

The weight hierarchies of a linear [n,k;q] code C satisfying the Near-Chain condition are studied, almost all the weight hierarchies of such code are determined.

关键词： weight hierarchy Near-Chain condition difference sequence linear code.

Synchronous estimation of DTM and fractional vegetation cover in forested area from airborne LIDAR height and intensity data

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Science china(Technological sciences) 2008年第S2期51卷 176-187页

作者： BAO YunFei1,2,CAO ChunXiang1,ZHANG Hao1,CHEN ErXue3,HE QiSheng1,2,HUANG HuaBing1,LI ZengYuan3,LI XiaoWen1,4 & GONG Peng1 1 state key laboratory of Remote Sensing Science,jointly sponsored by the Institute for Remote Sensing Applications of chinese academy of sciences and beijing Normal university,beijing 100101,china 2 graduate university of the chinese academy of sciences,beijing 100049,china 3 Institute of Forest Resource information Technique,the chinese academy of Forestry,beijing 100091,china 4 Research Center for Remote Sensing and GIS,Department of Geography and beijing key laboratory for Remote Sensing of Environment and Digital Sites,beijing Normal university,beijing 100875,china state key laboratory of Remote Sensing Science jointly sponsored by the Institute for Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China graduate university of the chinese academy of sciences Beijing China Institute of Forest Resource information Technique the Chinese Academy of Forestry Beijing China Research Center for Remote Sensing and GIS Department of Geography and Beijing Key Laboratory for Remote Sensing of Environment and Digital Sites Beijing Normal University Beijing China

We proposed a method to separate ground points and vegetation points from discrete return,small footprint airborne laser scanner data,called skewness change *** method,which makes use of intensity of laser scanner data,is especially applicable in steep,and forested *** does not take slope of forested area into account,while other algorithms consider the change of slope in steep forested *** ground points and vegetation points can be used to estimate digital terrain model(DTM) and fractional vegetation cover,respectively.A few vegetation points which were classified into the ground points were removed as noise before the generation of *** method was tested in a test area of 10000 square meters.A LiteMapper -5600 laser system was used and a flight was carried out over a ground of 700―800 *** this tested area,a total number of 1546 field measurement ground points were measured with a total station TOPCON GTS-602 and TOPCON GTS -7002 for validation of DTM and the mean error value is -18.5 cm and the RMSE(root mean square error) is ±20.9 cm.A data trap sizes of 4m in diameter from airborne laser scanner data was selected to compute vegetation fraction *** of fractional vegetation cover was carried out using 15 hemispherical photographs,which are georeferenced to centimeter accuracy by differential *** gap fraction was computed over a range of zenith angles 10° using the gap light analyzer(GLA) from each hemispherical *** R2 for the regression of fractional vegetation cover from these ALS data and the respective field measurements is *** this study presents a method for synchronous estimation of DTM and fractional vegetation cover in forested area from airborne LIDAR height and intensity data.

关键词： LIDAR intensity skewness synchronous DTM fractional vegetation cover

A property-based attestation protocol for TCM

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Science china(information sciences) 2010年第3期53卷 454-464页

作者： FENG DengGuo1,2 & QIN Yu1,2 1state key laboratory of information security, Institute of Software, chinese academy of Science, beijing 100190, china 2National Engineering Research Center of information security, beijing 100190, china state key laboratory of information security Institute of Software Chinese Academy of Science Beijing China National Engineering Research Center of information security Beijing China

This paper presents a property attestation protocol for the security chip TCM (trusted cryptographic module) via analyzing the problems of the current property attestation, which is built on the property attestation model with the online trust third party. In the protocol the prover utilizes the zero-knowledge proof by the attribute certificates, configuration commitment and TCM signature, and attests its configuration and status which are compliant with the declarative security property. The protocol is characterized by shorter signature length and lower computations. The security of the protocol is proved at the random oracle model. The protocol can help extend application and improve standard for security chip TCM, and it also has practical value and immediate significance.

关键词： trust computing trust cryptographic module (TCM) property attestation signature of knowl- edge configuration commitment