检索结果-南通市图书馆

Formal analysis and design of multi-party fair exchange protocols

在线全文

学校读者我要写书评

暂无评论

Science in China(Series F) 2006年第2期49卷 155-174页

作者： QING Sihan1,2.3.& LI Gaicheng1,3.1. Engineering {2. center for {2. {3. technology, Institute of Software, Chinese academy of sciences, beijing 100080, China 2. beijing Zhongke Ansheng Corporation of {2. technology, beijing 100080, China 3. Graduate School of the Chinese academy of sciences, beijing 10003., China Engineering research center for {2. {3. technology Institute of Software Chinese Academy of Sciences Beijing China beijing Zhongke Ansheng Corporation of information {2. Beijing China Graduate School of the Chinese academy of sciences Beijing China

Based on the origin of message items and channel combination between transacting parties, and events and relations among events, this paper presents a concise, precise, and hierarchical model for general fair exchange protocols, formally specifies various security requirements which are able to reflect inherent requirements for fair exchange protocols more rigorously, and partition these security requirements with fine granularity. This work helps analyze, debug, and design multi-party fair exchange protocols more effectively and elaborately,

关键词： fair exchange logical protocol formal model security requirement.

Mechanism and Defense on Malicious Code

在线全文

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural sciences 2005年第1期10卷 83-88页

作者： WEN Wei-ping 1,2.3. QING Si-han 1,2.3.1. Institute of Software, the Chinese {2. of sciences,{2., China 2.Engineering {3. center for information security technology, the Chinese {2. of sciences,{2., China 3.Graduate School of the Chinese {2. of sciences,{2., China Institute of Software the Chinese Academy of Sciences Beijing China Engineering research center for {2. {3. technology the Chinese Academy of Sciences Beijing China Graduate School of the Chinese academy of sciences Beijing China

With the explosive growth of network applications, the threat of the malicious code against network security becomes increasingly serious. In this paper we explore the mechanism of the malicious code by giving an attack model of the malicious code, and discuss the critical techniques of implementation and prevention against the malicious code. The remaining problems and emerging trends in this area are also addressed in the paper.

关键词： malicious code attacking model mechanism defense system security network security

Identifying heavy hitters in high-speed network monitoring

在线全文

学校读者我要写书评

暂无评论

Science China(information sciences) 2010年第3期53卷 659-676页

作者： ZHANG Yu1, FANG BinXing1,2.& ZHANG YongZheng2.1research center of Computer Network and {2. {3. technology, Harbin Institute of technology, Harbin 150001, China 2.0} center of {2. {3., Institute of Computing technology, Chinese academy of {12., {13. 100190, China research center of Computer Network and {2. {3. technology Harbin Institute of Technology Harbin China research center of {2. {3. Institute of Computing Technology Chinese Academy of Sciences Beijing China

Identifying heavy hitters in a network traffic stream is important for a variety of network applications ranging from traffic engineering to anomaly detection such as detection of denial-of-service attacks. Existing methods generally examine newly arriving items in the stream, perform a small number of operations using a small amount of memory, and still provide guarantees on the identifying accuracy. In high-speed network monitoring, the update speed per item is extremely critical. However, so far as we know, there are no identifying algorithms which can provide constant update time (O(1)) in a weighted data stream. In this paper, we present an algorithm named Weighted Lossy Counting (WLC) which is able to identify heavy hitters in a high-speed weighted data stream with constant update time. WLC employs a novel efficient partially ordered data structure which is able to provide a fast per-item update speed while keeping the memory cost relatively low. We compare WLC with state-of-the-art algorithms for finding heavy hitters in real traffic traces. The experimental results show that WLC performs well in accuracy (recall, precision and average relative error) as other algorithms; moreover it has a much higher update speed at the cost of relatively larger memory space used. A theoretical worst-case memory bound of WLC is also derived in this paper; however, experiments with long real traffic traces show that WLC requires much less space than the theoretical bound in practice.

关键词： network traffic monitoring heavy hitter weighted data streams

Polynomial analysis of canopy spectra and biochemical component content inversion

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Earth sciences 2005年第10期48卷 1780-1791页

作者： YAN Chunyan1, LIU Qiang1, NIU Zheng1, WANG Jihua2. HUANG Wenjiang2.& LIU Liangyun 2.1. State Key Laboratory of Remote Sensing Science, Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese academy of sciences and {2. Normal University, {2. 100101, China 2. National Engineering research center for information technology in Agriculture, {2. 100089, China Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese academy of sciences and {2. Normal University National Engineering research center for {2. {3. in Agriculture

A polynomial expression model was developed in this paper to describe directional canopy spectra, and the decomposition of the polynomial expression was used as a tool for re-trieving biochemical component content from canopy multi-angle spectra. First, the basic formula of the polynomial expression was introduced and the physical meaning of its terms and coeffi-cients was discussed. Based on this analysis, a complete polynomial expression model and its decomposition method were given. By decomposing the canopy spectra simulated with SAILH model, it shows that the polynomial expression can not only fit well the canopy spectra, but also show the contribution of every order scattering to the whole reflectance. Taking the first scattering coefficients a10 and a01 for example, the test results show that the polynomial coefficients reflect very well the hot spot phenomenon and the effects of viewing angles, LAI and leaf inclination angle on canopy spectra. By coupling the polynomial expression with leaf model PROSPECT, a canopy biochemical component content inversion model was given. In the simulated test, the canopy multi-angle spectra were simulated by two different models, SAILH and 4-SCALE re-spectively, then the biochemical component content was retrieved by inverting the coupled polynomial expression + PROSPECT model. Results of the simulated test are promising, and when applying the algorithm to measured corn canopy multi-angle spectra, we also get relatively accurate chlorophyll content. It shows that the polynomial analysis provides a new method to get biochemical component content independent of any specific canopy model.

关键词： polynomial expression, canopy spectra, decomposition, biochemical component content, inversion.

A three-dimensional variational ocean data assimilation system:Scheme and preliminary results

在线全文

学校读者我要写书评

暂无评论

Science China Earth sciences 2006年第11期49卷 1212-1222页

作者： ZHU Jiang1,2. ZHOU Guangqing1, YAN Changxiang1, FU Weiwei1 & YOU Xiaobao1,3.1. International center for Climate and Environment {2., Institute of Atmospheric Physics, Chinese {2. of {2., beijing 10002., China 2. Jiangsu Key Laboratory of Meteorological Disaster, Nanjing University of information Science and technology, Nanjing 2.0044, China 3. beijing Institute of Applied Meteorology, beijing 10002., China International center for Climate and Environment sciences Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Jiangsu Key Laboratory of Meteorological Disaster Nanjing University of Information Science and Technology Nanjing China beijing Institute of Applied Meteorology Beijing China

A new 3.VAR-based Ocean Variational Analysis System (OVALS) is developed. OVALS is capable of assimilating in situ sea water temperature and salinity observations and satellite altimetry data. As a component of OVALS, a new variational scheme is proposed to assimilate the sea surface height data. This scheme considers both the vertical correlation of background errors and the nonlinear temperature-salinity relationship which is derived from the generalization of the linear balance constraints to the nonlinear in the 3.VAR. By this scheme, the model temperature and salinity fields are directly adjusted from the altimetry data. Additionally, OVALS can assimilate the temperature and salinity profiles from the ARGO floats which have been implemented in recent years and some temperature and salinity data such as from expendable bathythermograph, moored ocean buoys, etc. A 2.-year assimilation experiment is carried out by using OVALS and the Tropical Pacific circulation model. The results show that the assimilation system may effectively improve the estimations of temperature and salinity by assimilating all kinds of observations. Moreover, the root mean square errors of temperature and salinity in the upper depth less than 42. m reach 0.63. and 0.3. psu.

关键词： data assimilation, 3.VAR, sea surface height, ARGO floats.

Another ID-Based Proxy Signature Scheme and Its Extension

在线全文

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural sciences 2007年第1期12卷 33-36页

作者： ZHANG Jianhong1,2., ZOU Wei3.1. College of Science, North China University of technology, {2. 100041,China 2. Institute of Software of Chinese {2. of {3. /State Key Laboratory of information security, beijing 100080, China 3. Institute of Computer Science and technology, Peking University, {2. 100871, China College of Science North China University of Technology Beijing China State Key Laboratory of information security Institute of Software of Chinese Academy of Sciences Beijing China Institute of Computer Science and technology Peking University Beijing China

So fur, the security of many proxy signatures has seldom been considered in a formal way and most of them cannot satisfy nonepudiation. In this work, a novel ID-based （Identity-based） proxy signature scheme is proposed by combining the proxy signature with ID-based public cryptography, and they formalize the notion of security for ID-based proxy signature schemes. And show that the security of the proposed scheme is secure. Compured with other proxy signature schemes, it does not need a secure channel. Thus, it is particularly suitable for the unreliable network computation environment. Finally, they extend proposed scheme to a proxy multi-signature which has the following advantages （1） the size of proxy multi- signature is independent of the number of delegating users; （2. the computation cost of proxy multi-signature only need two Weil paring.

关键词： proxy signature multisignature security proof

Black-box testing based on colorful taint analysis

在线全文

学校读者我要写书评

暂无评论

Science China(information sciences) 2012年第1期55卷 171-183页

作者： CHEN Kai1,2.3.FENG DengGuo1,SU PuRui1&ZHANG YingJun1,2.3.1State Key Laboratory of {2. security,Institute of Software,Chinese {2. of Science,{3. 100190,China 2.tate Key Laboratory of {2. security,Graduate University of Chinese {2. of sciences,{3. 100049,China 3.ational Engineering {12. center of {2. security,{3. 100190,China State Key Laboratory of information security Institute of Software Chinese Academy of Science Beijing China State Key Laboratory of information security Graduate University of Chinese Academy of Sciences Beijing China National Engineering research center of {2. {3. Beijing China

Software vulnerability detection is one of the most important methods for guaranteeing software *** main classes of methods can detect vulnerabilities in binary files:white-box testing and black-box *** former needs to construct and solve path constraints to detect *** has two main drawbacks:path exploding and complexity of *** latter often aimlessly exhausts various inputs to test binary *** paper combines both testing methods to detect vulnerabilities in binary *** analyzing the input elements that aect check condition corresponding to a certain check point,we can generate one class of inputs that get to the check point to increase fuzzing *** analyzing the relationship between guard conditions and check condition,the redundant check points are *** taint analysis method(CTAM)is proposed to compute guard conditions,which is more ecient than traditional taint analysis method(TTAM).We implemented a prototype and made several experiments on *** results showed that our method could increase the eciency of black-box testing.

关键词： software testing vulnerability detection dynamic testing black-box testing colorful taint analysis

Threshold quantum secure direct communication without entanglement

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2008年第2期51卷 176-183页

作者： YANG YuGuang1,3.& WEN QiaoYan2.1 College of Computer Science and technology, {2. University of technology, {2. 10002., China 2.School of Science, {2. University of Posts and Telecommunications, {2. 100876, China 3.State Key Laboratory of information security (Graduate School of Chinese academy of sciences), {2. 100049, China College of Computer Science and technology Beijing University of Technology Beijing China State Key Laboratory of information security (Graduate School of Chinese {2. of {3.) Beijing China School of Science Beijing University of Posts and Telecommunications Beijing China

For the first time, a threshold quantum secure direct communication (TQSDC) scheme is presented. Similar to the classical Shamir's secret sharing scheme, the sender makes n shares, S1, …, Sn of secret key K and each receiver keeps a share secretly. If the sender wants to send a secret message M to the receivers, he en-codes the information of K and M on a single photon sequence and sends it to one of the receivers. According to the secret shares, the t receivers sequentially per-form the corresponding unitary operations on the single photon sequence and ob-tain the secret message M. The shared shares may be reusable if it can be judged that there is no eavesdropper in line. We discuss that our protocol is feasible with current technology.

关键词： quantum secure direct communication threshold secure direct communication quantum secret sharing

Seasonal variation of global stratosphere-troposphere mass exchange

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第12期17卷 1466-1475页

作者： Guo Dong1,2. Lu Daren2.and Sun Zhaobo1(1. Institute of Atmospheric sciences, Nanjing University of information Science and {2., Nanjing 2.0044, China 2. LAGEO, Institute of Atmospheric Physics, Chinese {3. of sciences, beijing 10002., China) Institute of Atmospheric sciences Nanjing University of Information Science and Technology Nanjing 210044 China LAGEO Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

By Wei formula in pressure coordinate, the stratosphere-troposphere mass exchange (STME) is diagnosed globally for 44 years from 1958 to 2.01 using the European center for Medium-Range Weather Forecasts (ECMWF) reanalysis datasets. Regions of mass flux into the stratosphere are found over Indonesia, bay of Bangladesh and the mid-west coast of South Africa. Compensating mass outflow from the stratosphere appears mainly over mid-latitudes near large-scale troughs. Upward and downward transport of mass at the middle and high latitudes accompany with each other. Mass flux into troposphere is stronger in autumn and winter than in spring and summer. Strong downward mass flux into the troposphere occurs in eastern Asia the whole year with nearly stable sites. Although the area of eastern Asia accounts for only 5.6% of that of the northern hemisphere (NH), its net mass exchange reaches 15.83. of that of the NH, which means that {2. on STME of eastern Asia is greatly important to that of the NH and even the global areas. Air across the tropopause enters more from stratosphere to troposphere than that from troposphere to stratosphere, which is possibly related with systematic bias of the assimilated datasets and with persistent rise of the tropopause height. Contributions of the mass exchange and the mass flux exchange in the NH and southern hemisphere (SH) on their latitudes increase from equator to pole, with larger contributions in the NH. Mass exchange and mass flux exchange per areas at high latitudes are larger than that at low latitudes, which means greater mass exchange efficiency at high latitudes.

关键词： stratosphere troposphere mass exchange seasonal variation.