基于Diffie—Hellman的一次性口令认证方案

针对目前一次性口令的不足,借鉴质询/响应方案的思想设计了一种基于Diffie-Hellman的一次性口令认证方案.与传统方案相比,该方案不仅能够提供通信双方的相互认证,而且能够抵抗重放攻击、离线口令猜测攻击和假冒攻击,极大地增强了应用系统的安全性.     

一种增强的智能卡口令鉴别方案

分析了Zhang等提出的身份鉴别方案,指出了其不能抵抗离线口令猜测攻击,以及在登录阶段和验证阶段存在设计缺陷等问题.然后在保留其优点的基础之上,通过引入随机数和增加登录请求信息的方法,提出了一种更加安全可靠的口令认证协议方案.安全性分析结果表明,该方案能够有效抵抗离线口令猜测攻击和假冒攻击,可以实现双向鉴别等特点,增强了系统的安全性和实用性.     

基于动态口令的应用层DDoS攻击防御方案

研究和设计了使用动态口令技术来保护服务器抵御DDoS攻击的OTP-DEF方案.首先,方案可根据服务器工作负载的不同,分别处于正常、疑似受攻击或确认受攻击3种工作模式之下,而基于动态口令的认证方案只在疑似受攻击工作模式下起作用.其次,由于动态口令会自动变化,故方案可抵御复制、重放和暴力破解攻击.第三,通过记录那些不解决难题并不断发送请求的IP地址来识别客户端是否为攻击者,一旦所有攻击者被识别出来后,OTP-DEF屏蔽其IP地址并停止发布难题,以便正常用户能方便地使用服务.最后,只需在服务器端实施和部署,客户端无需做任何更改.     

一种基于智能卡的有效远程双向鉴别方案

提出了一种基于智能卡的有效远程双向身份鉴别方案。用户可自由地选择和改变登录口令,无需维护口令目录表或验证表。此外,该方案不仅能够提供通信双方的相互鉴别,而且引入质询随机数代替时间戳,既可保证每次身份鉴别信息的随机性,有效防止重放攻击,又避免了复杂的时间同步问题,极大地增强了应用系统的安全性和实用性。     

安全的非智能卡匿名口令认证方案

对Rhee-Kwon-Lee非智能卡(SC)口令认证方案进行安全分析发现,此方案易受内部攻击,不能实现口令自由更换,并且计算效率不高.基于此提出了一种新的基于散列函数的非SC匿名口令认证方案,新方案采用匿名身份与口令混淆,并结合时间戳来提高安全性和计算效率.新方案弥补了Rhee-Kwon-Lee方案的安全缺陷.而且,与其他同类非SC方案相比较,新方案支持文中理想的非SC口令认证方案的所有安全需求,安全性能最好且计算量小.     

一种基于智能卡的远程双向身份鉴别方案

分析了Hu等人提出的基于智能卡的远程身份鉴别方案,发现该方案易遭受重放攻击和口令猜测攻击;提出了一种基于质询／响应和用户通行密语的改进方案,改进方案能抵抗重放攻击、口令猜测攻击、假冒服务攻击,同时具有较好的可修复性,最后对Hu方案和改进方案的效率进行了比较。改进方案保留了原方案中使用智能卡的优点,且具有更高的安全性。     

基于智能卡的轻量级非平衡型口令认证方案

智能卡与口令相结合的身份认证方式既可保留使用强密钥优势,又具有使用方便的特点,是一种理想的安全双因子认证方式。当前许多公开的口令认证方案,要么需要较强的计算环境而难于采用智能卡快速实现,要么不能抵抗离线口令猜测攻击或服务端内部攻击而存在安全缺陷。提出一种非平衡型口令认证方案,基于智能卡和用户口令双因子设计,具有简便高效、口令安全、双向认证特点,能够抵御离线口令猜测攻击和服务端内部攻击,可用于满足设备开机时的安全认证需求。     

一种适于受限资源环境的远程用户认证方案的分析与改进

该文讨论了Fang等人(2011)新近提出的一个安全高效的基于智能卡的远程用户口令认证方案,指出原方案无法实现所声称的抗离线口令猜测攻击,对平行会话攻击和已知密钥攻击是脆弱的,并且存在用户口令更新友好性差问题。给出一个改进方案,对其进行了安全性和效率分析。分析结果表明,改进方案弥补了原方案的安全缺陷,保持了较高的效率,适用于安全需求较高的资源受限应用环境。     

基于置乱排序的身份认证协议研究

在分析经典的身份认证方案,特别是一次性口令认证方案中S/KEY方案存在问题的基础上,提出了一种新的身份认证协议COTP在本协议中,采用了基于混沌置乱排序表的设计算法,在用户登录过程中用置乱排序后的次数代替真正的迭代次数,对协议中用到的种子进行了加密处理.理论分析与仿真实验表明,COTP认证协议能抵御小数攻击、重放攻击及内部人员攻击,能对传输的种子和迭代次数进行加密,并实现了客户和服务器的双向认证.     

一种改进的动态ID远程用户身份认证方案

由于网络安全的需要,利用智能卡的双因子身份鉴别方案越来越受到重视。首先分析了Wang Yan-yan等人提出的基于动态ID的远程用户身份认证方案的安全性,指出其方案的安全缺陷是不能抵抗离线的口令猜测攻击;随后提出了一种改进的方案,改进之后的方案能有效抵抗重放攻击、离线口令猜测攻击、假冒服务器/用户攻击。经过安全分析,新的方案在保留了原方案优点的同时,具有了更高的安全性。     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.