改进的Rabin密码体制安全性分析

Shamir和Schorr对Rabin数字签名方案提出一种有效的攻击方法,称为Shamir攻击.为了避免Shamir攻击,本文提出一种有效的比特位扰乱法(Bit Perturbation).基于Rabin公钥密码体制,Harn和Kiesler提出一种改进的公钥密码体制、数字签名方案和认证加密方案.本文指出Harn和Kiesler提出的密码体制是不安全的,并设计一种安全的数字签名方案.     

基于智能卡的RSA数字签名实现关键问题解析

数字签名是一种应用于网络安全的重要安全机制,智能卡或Token是用来实现数字签名验证的安全硬件载体,如何在硬件载体上实现数字签名是一个较为关键的问题.本文根据接触式智能卡系列标准及PKCS (Public Key Cryptographic Standard)系列相关标准,成功实现了智能卡操作系统上的RSA(一种非对称公钥密码算法)算法下的数字签名、身份认证、信息加解密、密钥分配,并着重解析了应用中智能卡RSA算法实现方面的关键问题,提出了若干解决方案.     

密码体制与消息认证技术

消息认证在现代技术上的实现又称为数字签名，而公钥密码技术的出现为数字签名的真正推广提供了坚实的技术基础。本文比较详细地介绍了公钥密码技术、消息认证技术的一般、消息认证技术的发展，重点介绍了实际应用中如何利用对称密码和设备的一些性质来构成数字签名的体制的方法。     

基于PKI的网络教学系统信息安全策略

网络教学发展非常迅速,但是相应的网络安全措施还相对滞后.文中结合网络教育的一般模式和公钥密码系统,通过对网络教学模式的通信安全需求分析,提出对网络教学过程中基于公钥系统的信息加密,身份认证、数字签名等信息安全策略应用模式,并对网络教学中的信息安全模式进行风险评价,确保教学信息的安全、学生身份的认证,保障了网络教学的安全和顺利进行.     

一种生物特征与公钥密码相结合的多层次身份认证方案

信息安全技术是保障各种网络应用正常运作的必要支撑,而身份认证是信息安全保障技术的重要组成部分。丈中简单分析了传统网络身份认证技术存在的安全缺陷,然后介绍了生物特征识别技术及其国内外应用情况。最后提出了一种把生物特征识别技术与公钥密码技术相结合的多层次身份认证方案,该方案解决了传统身份认证方案的部分缺点,增强了身份认证安全性,为实现更为安全可靠的网络安全体系提供技术支撑。     

基于流认证的IPv6接入子网主机源地址验证

提出了一种以密码学方法实现的IPv6接入子网主机高速源地址验证方案。把主机MAC地址作为身份同主机公钥相绑定,利用密码生成地址算法从主机公钥衍生出IPv6接入子网地址,通过数字签名提供主机真实性的验证,以消息认证码和流认证技术实现接入网关对数据分组流IPv6地址的快速安全的验证。原型系统实验表明,该方案能够以低开销实现数据分组源地址验证,是一种安全、可行的方案。     

“网络银行安全支付系统”的设计与实现

探讨了“网络银行安全支付系统”方案的设计与实现,提出了这一方案的设计模型,重点讨论了基于公钥密码体制和私钥密码体制的身份鉴别、数据加密、数字签名等现代密码技术在“网络银行安全支付系统”中的应用。     

XTR体制下基于身份特征的数字签名算法

XTR公钥体制是一种基于子群离散对数问题的密码体制,同现在流行的RSA公钥体制相比,它的密钥长度短,传输效率高;同椭圆曲线公钥体制相比,它的密钥选取简单,计算速度快.因而,从XTR公钥体制被提出以来就倍受关注,本文首次提出了XTR体制下基于身份特征数字签名算法和基于身份特征的数字盲签名算法,这为XTR数字签名算法提供了更为广阔的应用领域.文中证明了这两种算法的安全性,并对其特性和效率进行了分析.这两种数字签名对电子商务和电子政务的发展具有重要价值.     

基于指纹USBkey的Kerberos改进协议

Kerberos协议容易遭受口令攻击和重放攻击,且不能提供数字签名服务。针对这些问题,文中结合公钥密码体制、USB智能卡以及指纹识别技术对Kerberos协议加以改进,改进后的协议能够充分利用公钥密码体制的优点,极大降低密钥管理的风险和难度。此外,相比其他仅使用公钥密码体制的改进方案,本方案由于使用了指纹USBkey,实现了对系统使用者物理身份的认证,并节省了使用或建设认证机构CA的开销,使协议更适用于高安全应用场合。     

基于椭圆曲线密码体制的安全电子邮件系统

针对电子邮件在传输过程中存在的安全问题，提出了一种基于三重DES和椭圆曲线密码体制的解决方案。其公钥管理是借鉴PGP系统管理公钥的方法；进而重点介绍了邮件的加密／解密、签名／验证的过程，有效地解决了电子邮件系统中的加密、签名和身份认证问题。     

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.     

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.     

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.     

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.     

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.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

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.