InGaAs/InP盖革模式雪崩焦平面阵列的研制

设计制作了一种由InGaAs/InP雪崩光电二极管阵列与时间计数型CMOS读出电路组成的8×8阵列规格盖革模式雪崩焦平面阵列(GM APD FPA).雪崩光电二极管采用SAGCM结构,在盖革模式下工作具有单光子探测灵敏度;时间计数型CMOS读出电路在每个单元获取光子飞行时间,实现纳秒级的时间分辨率,并完成雪崩淬灭功能.测试结果表明,倒装混合集成的GM APD FPA器件暗计数率(DCR)均值为32.5 kHz,单光子探测效率(PDE)均值为19.5％,单元时间抖动为465 ps,实现了光脉冲时间信息的探测,验证了盖革模式雪崩焦平面阵列技术及其在三维成像中应用的可行性.     

面向信息隐藏的图像复杂度研究

图像位平面复杂度与人的视觉感受有着密切得关系,研究图像位平面复杂度对图像信息隐藏研究意义重要.本文提出了复杂度度量的新方法,把图像位平面的信息熵作为图像复杂度测度.研究了随机序列游长统计规律,并给出理论推导,利用图像位平面的游程统计规律与随机序列游程统计规律的接近程度,定量地描述了图像复杂度,并从实际应用的角度分析了其合理性,说明了图像位平面复杂度可以作为图像信息隐藏的性能评价指标.     

广义自缩序列的游程长度

广义自缩序列是一类新型的序列密码.游程长度是衡量序列伪随机性质的一个重要指标,一个好的伪随机序列应该具有短的游程长度.本文利用m序列的伪随机性质,研究了广义自缩序列的游程长度,得到如下结果:广义自缩序列族中除两个序列(全0序列和全1序列)外,其余序列的游程长度不超过n×n-2.5n+3,在n为偶数的情况下,游程长度不超过n×n/2-1.25n+3.     

雪崩二极管

利用半导体二极管中雪崩现象制作的微波振荡器件、放大器件总称为雪崩二极管。在这种二极管中,由于杂质分布或外电路不同,其工作机理也不尽相同,因而有几种振荡模式,但其中碰撞雪崩渡越时间模式(IMPATT-IMPact Avalanche Transist Time)和俘获等离子体雪崩触发渡越模式(TRAPATT-TRApped Plasma Avalanche Triggered Transit)最有实用价值。     

X波段GaN MMIC低噪声放大器设计

采用SiC衬底0.25 μm AlGaN/GaN高电子迁移率晶体管(HEMT)工艺,研制了一款X波段GaN单片微波集成电路(MMIC)低噪声放大器(LNA).放大器采用三级级联拓扑,第一级采用源极电感匹配,在确保良好的输入回波损耗的同时优化放大器噪声系数;第三级采用电阻电容串联负反馈匹配,在尽量降低噪声系数的前提下,保证良好的增益平坦度、输出端口回波损耗以及输出功率.在片测试表明,在10 V漏级电压、-2 V栅极电压偏置下,放大器静态电流为60 mA,8～12 GHz内增益为22.5 dB,增益平坦度为±1.2 dB,输入输出回波损耗均优于-11 dB,噪声系数小于1.55 dB,1 dB增益压缩点输出功率大于11.9 dBm,其芯片尺寸为2.2 mm×1.1 mm.装配测试表明,噪声系数典型值小于1.6 dB,可承受33 dBm连续波输入功率.该X波段GaN低噪声放大器与高功率放大器工艺兼容,可以实现多功能集成,具有广阔的工程应用前景.     

InGaAs／InGaAsP／InP长波长雪崩光电二极管研究

研制了高速、高效、低噪声的InGaAs/InGaAsP/InP长波长(1.0～1.7μm)台面型雪崩光电二极管(φ=75μm),器件采用分离的吸收区、雪崩区和能隙过渡区的SAGM结构。研究了器件最佳结构参数设置、在InP上匹配生长InGaAs、InGa AsP及其厚度和载流子浓度的控制问题。器件最大倍增因子大于50,灵敏度大于0.70μA/μW,暗电流I_D的典型值约为20nA(V_r=0.9V_B)。     

IC芯片视觉检测中快速图像匹配定位

利用IC芯片定位图像特征,提出一种用其投影特征的基于优势遗传自适应遗传算法(AGA)的快速匹配算法(P-AGA)。设计基于图像灰度投影特征的匹配规则,使算法适应于一定的噪声、缩放、旋转和变形图形,而且运算量小。对图像采用2×2重采样,使运算量降低3/4。匹配过程是在二维图像空间的随机寻优,提出优势遗传的AGA,用匹配距离作为适应度函数,并自适应改变交叉变异概率进行匹配寻优,快速准确求出全局最优匹配点。实验表明,该算法比标准遗传算法(SGA)快约1.9倍,准确度提高约22.5%,有效提高匹配速度和准确度,有很强的抗噪声能力,鲁棒性好。     

一种Android应用安全审核认证系统的设计方案

针对恶意APK文件泛滥问题,综合静态、动态安全检测和APK重签名技术,设计了一套安全的Android应用审核认证系统,它由基于Web应用的安全审核平台和智能终端APK安全认证模块构成。安全审核平台利用强健的调度子系统完成了批量APK应用的提交、安全检测、重签名、发布及统计查询功能,保证了发布到官方应用商城中APK的安全性;智能终端APK安全认证模块引入了新型的重签名技术,可有效判断APK应用是否由"官方"安全认证。由此可见,该系统从"源"(应用商城)到"端"(智能终端)保障了APK文件的安全。     

基于身份的认证密钥协商协议的安全分析与改进

对基于身份的标准模型下可证明安全的认证密钥协商协议进行安全性分析,发现恶意的密钥生成中心(PKG,pfivate key generator)能计算出所有的会话密钥,即它在无会话密钥托管模式下不满足PKG前向安全性.因此,为满足无托管的要求,提出一个改进的基于身份的认证密钥协商协议,并在标准模型下证明其为安全的认证密钥协商协议.结果表明,改进后协议满足完善前向安全性和PKG前向安全性.     

一种基于手形特征点匹配的身份认证方法

该文提出了一种基于手形的身份认证方法。该方法首先通过对手形图像的处理,将手形表示为由一系列有序点构成的特征点集,然后应用基于确定性退火技术的点匹配算法对两个手形的特征点集进行匹配,得到用于认证的两个匹配参数:平均匹配误差和匹配率,最后设计适当的分类器,对匹配结果进行分类判决,实现身份认证。考虑到在手形认证的研究中都是小样本情况,因此首次将建立在统计学习理论(SLT)基础之上的支持向量机(SVM)应用于手形的认证中,得到的结果是令人满意的。实验证明,与现有的手形认证方法相比,该文的方法不仅提高了认证的准确性,而且增强了认证的鲁棒性。     

Multi-block chaining-based authentication mode

A fast authentication mode based on Multi-Block Chaining （MBC） is put forward; and its security is proved. The MBC mode is for new generation block cipher algorithms. Its speed is about 13% faster than that of the authentication modes in common use （for example, cipher block chaining-message authentication code mode）. The dependence test results meet the requirement. The MBC mode is complete; its degree of avalanche effect is about 0.9993; its degree of strict avalanche criterion is 0.992 or so. The frequency test results indicate that the output generated by the MBC mode has uniformity. The binary matrix rank test results imply that it is linear independent among disjoint sub-matrices of the output. Maurer＇s universal statistical test results show that the output could be significantly compressed without loss of information. Run test, spectral test, non-overlapping template matching test, overlapping template matching test, Lempel-Ziv compression test, linear complexity test, serial test, approximate entropy test, cumulative sums test, random excursions test and random excursions variant test results fulfill the requirements of all. Therefore the MBC mode has good pseudo-randomness. Thus the security of MBC mode is verified by the way of statistical evaluation.     

Efficient and privacy-preserving online face authentication scheme

In traditional face authentication system,the trait template and authentication request were generally matched over plaintext,which may lead to the leakage of users’ sensitive data.In order to address the above-mentioned problem,based on matrix encryption,an efficient and privacy-preserving online face authentication scheme was proposed.Specifically,the users’ face trait template for register and the authentication request were encrypted before being sent to the online authentication server,and the similarity computation between the encrypted face trait template and authentication request was computed by the online authentication server over ciphertexts,which guaranteed the security of users’ sensitive data without affecting the accuracy of face authentication.Security analysis shows that the proposed scheme can achieve multiple security levels according to different security parameters.Moreover,performance evaluation shows that the proposed scheme has low computation cost and communication overhead.Experiments results demonstrate the high efficiency of the proposed scheme,which can be implemented in the real environment effectively.     

A secure fingerprint template generation mechanism using visual secret sharing with inverse halftoning

Fingerprints are the most popular and widely practiced biometric trait for human recognition and authentication. Due to the wide approval, reliable fingerprint template generation and secure saving of the generated templates are highly vital. Since fingers are permanently connected to the human body, loss of fingerprint data is irreversible. Cancelable fingerprint templates are used to overcome this problem. This paper introduces a novel cancelable fingerprint template generation mechanism using Visual Secret Sharing (VSS), data embedding, inverse halftoning, and super-resolution. During the fingerprint template generation, VSS shares with some hidden information are formulated as the secure cancelable template. Before authentication, the secret fingerprint image is reconstructed back from the VSS shares. The experimental results show that the proposed cancelable templates are simple, secure, and fulfill all the properties of the ideal cancelable templates, such as security, accuracy, non-invertibility, diversity, and revocability. The experimental analysis shows that the reconstructed fingerprint images are similar to the original fingerprints in terms of visual parameters and matching error rates.     

Discriminative common vector based finger knuckle recognition

The main issue in personal authentication systems for military, security, industrial and social applications is accuracy. This paper presents a finger knuckle print (FKP) recognition approach to identity authentication. It applies a discriminative common vectors (DCV) based method to obtain the unique feature vectors, called discriminative common vectors, and the Euclidean distance as matching strategy to achieve the identification and verification tasks. The recognition process can be divided into the following phases: capturing the image; pre-processing; extracting the discriminative common vectors; matching and, finally, making a decision. In order to test and evaluate the proposed approach both the most representative FKP public databases and an established non-uniform FKP database were used. Experiments with these databases confirm that the DCV-based FKP recognition method achieves the authentication tasks effectively. The results showed the performance of the system in terms of the recognition rate had 100% accuracy for both training data and unseen test data.     

基于MRP的可撤销模板设计及其分析

 针对基于生物特征认证系统中的存储及传输安全问题,并且考虑到基于VQ(Vector Quantization)算法声纹认证系统训练数据少,存储空间和训练时间也比较小的优点,在基于VQ算法声纹认证系统的基础上,采用MRP(Multispace Random Projection)提出一种可撤销声纹模板.通过特征点与特征点,特征点与码字之间的距离变换前后保持不变,说明平均量化误差不变,从而证明该方法满足可撤销模板的性能保持性.通过随机矩阵和不定方程的分析证明该方法满足不可逆性,即是安全的.初步实验结果的认证率达96%,说明该方法的有效性.     

基于动态手势的身份认证方法及其在智能手机上的应用

基于生物特征的身份认证方法是当前信息安全技术领域的热点.论文在分析当前各种生物特征认证方法的基础上,针对其应用在智能手机上存在的问题,提出一种基于动态手势进行身份认证的算法EI-DTW.算法结合放宽端点限制和提前终止的动态时间规整（DTW）高效算法,取消了手势特征匹配时的端点对齐限制,提高了认证精度,并通过限定弯折斜率和提前终止策略进一步提高了认证效率.     

Fingerprint features-statistical analysis and system performanceestimates

As the need for personal authentication increases, many people are turning to biometric authentication as an alternative to traditional security devices. Concurrently, users and vendors of biometric authentication systems are searching for methods to establish system performance. This paper presents a model that defines the parameters necessary to estimate the performance of fingerprint-authentication systems without going through the rigors of intensive system testing inherent in establishing error rates. The model presented here was developed to predict the performance of the pore-based automated fingerprint-matching routine developed internally in the research and development division at the National Security Agency. This paper also discusses the statistics of fingerprint pores and the efficacy of using pores in addition to the traditionally used minutiae to improve system performance. In addition this paper links together the realms of automated matching and statistical evaluations of fingerprint features. The results of this link provides knowledge of practical performance limits of any automated matching routine that utilizes pores or minutia features     

Secure Face Authentication Framework in Open Networks

In response to increased security concerns, biometrics is becoming more focused on overcoming or complementing conventional knowledge and possession‐based authentication. However, biometric authentication requires special care since the loss of biometric data is irrecoverable. In this paper, we present a biometric authentication framework, where several novel techniques are applied to provide security and privacy. First, a biometric template is saved in a transformed form. This makes it possible for a template to be canceled upon its loss while the original biometric information is not revealed. Second, when a user is registered with a server, a biometric template is stored in a special form, named a ‘soft vault’. This technique prevents impersonation attacks even if data in a server is disclosed to an attacker. Finally, a one‐time template technique is applied in order to prevent replay attacks against templates transmitted over networks. In addition, the whole scheme keeps decision equivalence with conventional face authentication, and thus it does not decrease biometric recognition performance. As a result, the proposed techniques construct a secure face authentication framework in open networks.     

Trust based authentication technique for cluster based vehicular ad hoc networks (VANET)

Since Vehicular ad hoc networks (VANETs) are vulnerable to various kinds of attacks, there is a need to fulfill the security requirements like message privacy, integrity, and authentication. The authentication technique is said to be efficient if it detects compromised nodes accurately with less complexity, reduced authentication delay, and keying overhead. In this paper, a trust-based authentication scheme for cluster-based VANETs is proposed. The vehicles are clustered, and the trust degree of each node is estimated. The trust degree is a combination of direct trust degree and indirect trust degree. Based on this estimated trust degree, cluster heads are selected. Then, each vehicle is monitored by a set of verifiers, and the messages are digitally signed by the sender and encrypted using a public/ private key as distributed by a trusted authority and decrypted by the destination. This verifies the identity of sender as well as receiver thus providing authentication to the scheme. By simulation results, we prove that the proposed technique provides high security with less overhead and delay.     

RFID匿名认证协议的设计

在分析RFID协议安全需求的基础上,基于通用可组合安全模型,设计了一个低成本的RFID匿名认证协议,在标准模型下证明了RFID匿名认证协议的安全性.设计的协议提供匿名、双向认证和并发安全,并且协议的实现对于一般的RFID结构都是切实可行的.