Fingerprint-based key binding/recovering scheme based on fuzzy vault

This letter proposes fingerprint-based key binding/recovering with fuzzy vault. Fingerprint minutiae data and the cryptographic key are merged together by a multivariable linear function. First, the minutiae data are bound by a set of random data through the linear function. The number of the function＇s variables is determined by the required number of matched minutiae. Then, a new key derived from the random data is used to encrypt the cryptographic key. Lastly, the binding data are protected using fuzzy vault scheme. The proposed scheme provides the system with the flexibility to use changeable number of minutiae to bind/recover the protected key and a unified method regardless of the length of the key.     

具有空间、时间双重分布性的随机会话密钥分发系统

本文首先提出了分布式密码协议的空间分布性和时间分布性的观点,并从双重分布性的角度研究分布式密码协议.作为一个例子,在V.Daza的密钥分发系统中一个只具有空间分布性的分布式密钥分发系统的基础上,引入了前置安全(proactive security)体制,得到了一个具有空间和时间双重分布性,可以抵抗动态攻击者的分布式密钥分发协议.拓展了分布式密码协议的研究空间.同时,文中在建立概率空间的基础上,证明了分布式密钥分发系统的安全性.     

中点箝位型逆变器控制方法的综合研究

本文深入研究了空间矢量调制模式下的三电平逆变器中点电压波动的机理，建立了平均中点电流数学模型，为中点电压平衡控制提供了理论依据，并提出基于电压中矢量合成的中点电压平衡控制方法，该方法对于系统动态过程中出现的电压不平衡，可以通过调整冗余小矢量的相对作用时间进行补偿，由于电压中矢量的部分作用时间被均分给相应的小矢量，因此其补偿效果明显。实验结果证实了本文研究方法的正确性。     

传感器网络随机密钥对模型密钥管理方案改进

在传感器网络中有必要应用加密技术对节点间的通信进行保护。基于随机密钥对模型的传感器网络的密钥管理方案（BPKP），实现了包括初始密钥对向量预分配，通信密钥对向量的建立和通信密钥对向量更新。对BPKP的性能分析表明：BPKP具有高网络连通性、高安全性和低耗能的优点。     

基于RSA的电子政务访问控制系统模型

本文通过将对称加密和非对称加密相结合的加密体制应用于电子政务内网访问控制系统,利用非对称加密体制中密钥的非对称特性以及RSA主密钥、用户密钥的建立,实现了对于敏感数据和机密文件的访问控制,同时实现了基于角色的访问控制模型。     

基于稀疏约束的SAR目标特征提取方法研究

特征提取是合成孔径雷达目标识别关键技术与核心任务。为了更好地提取目标特征,稀疏约束将被添加在非负矩阵分解法中,并应用于图像目标特征提取,通过利用稀疏约束的非负矩阵分解方法对sAR目标图像进行分解,构建具有稀疏性的目标特征矢量,提高了特征矢量的类内相似性与类间差异性。利用基于支持向量机的分类方法对MSTAR数据进行目标识别试验,试验结果表明,添加稀疏约束的NMF方法与PCA、ICA以及一般NMF特征提取方法相比,能够显著提高目标识别的稳定性和准确率。     

FPGA implementation of highly secure,hardware‐efficient QC‐LDPC code–based nonlinear cryptosystem for wireless sensor networks

This paper presents the design and implementation of an integrated architecture for embedding security into quasi‐cyclic (QC) low‐density parity‐check (LDPC) code–based cryptographic system through a nonlinear function of low hardware complexity. Instead of using standard S ‐boxes for implementation of nonlinear function, this paper considers a method on the basis of maximum length cellular automata (CA), so that enhanced security can be achieved with simple hardware structure. The proposed system adopts a lightweight random bit stream generator on the basis of linear feedback shift register (LFSR) for generating random error vectors, so that a large number of vectors with very good cryptographic properties can be made available with low hardware cost. Different permutation patterns generated for different message blocks help to provide good degrees of freedom for tuning security with reasonable key size. The hardware architecture for the proposed system is developed and validated through implementation on Xilinx Spartan 3S500E. Analytical and synthesis results show that the proposed scheme is lightweight and offers very high security through continuously changing parameters, thus making it highly suitable for resource‐constrained applications.     

联合作战密钥分发架构设计

以联合作战使命任务需求为牵引,基于作战网络模型,提出了密码信息网络和密码任务群组概念;作战网络的动态性导致了密码任务群组的不确定性,从而增大了密钥的生成与分发难度。利用复杂网络的邻接矩阵机理设计了密码任务群组的计算方法,并对密码态势认知、密码网络建模、密钥的生成和分发路径等关键环节进行了分析研究。结合信息化条件下联合作战指挥特点,设计了分发流程和架构,实现了密钥自动生成和灵活动态调整,解决了特定战斗任务之不确定性、多样性和复杂性带来的密钥分发难题。有效提高了密钥分发科学化和规范化水平,为密钥分发系统与指挥信息系统的深度融合、与作战系统和通信网络系统的自动协同筹划奠定了基础。     

Frame-adaptive vector quantization for image sequence coding

An adaptive technique for image sequence coding that is based on vector quantization is described. Each frame in the sequence is first decomposed into a set of vectors. A codebook is generated using the vectors of the first frame as the training sequence, and a label map is created by quantizing the vectors. The vectors of the second frame are then used to generate a new codebook, starting with the first codebook as seeds. The updated codebook is then transmitted. At the same time, the label map is replenished by coding the position and the new values of the labels that have changed from one frame to the other. The process is repeated for subsequent frames. Experimental results for a test sequences demonstrate that the technique can track the changes and maintain a nearly constant distortion over the entire sequence     

Three systems for cryptographic protocol analysis

Three experimental methods have been developed to help apply formal methods to the security verification of cryptographic protocols of the sort used for key distribution and authentication. Two of these methods are based on Prolog programs, and one is based on a general-purpose specification and verification system. All three combine algebraic with state-transition approaches. For purposes of comparison, they were used to analyze the same example protocol with a known flaw.     

Neighbourhood-blocks motion vector estimation technique using pyramidal data structure

A pyramidal motion estimation technique that makes use of the motion correlation within a pyramidal level is proposed. In the proposed technique, motion vectors from neighbouring motion blocks are taken into consideration as possible candidates. This is done in lieu of scaling the motion vectors from the corresponding positions at the adjacent lower pyramidal level as the prediction motion vectors for the current pyramidal level (as performed in the conventional technique). Each of these candidate motion vectors is used as the prediction motion vector and refined, and the one that has the least matching distortion is chosen as the motion vector at the current pyramidal level. Compared to the conventional pyramidal motion estimation technique, the proposed method effectively overcomes the problem of propagation of false motion vectors. Simulation studies show that a substantial improvement is achieved in the performance, both in terms of the prediction mean square error and the number of coding bits for the motion vectors.     

A subtree‐based transformation model for cryptosystem using chaotic maps under cloud computing environment for fuzzy user data sharing

Cloud computing technologies have been prospering in recent years and have opened an avenue for a wide variety of forms of adaptable data sharing. Taking advantage of these state‐of‐the‐art innovations, the cloud storage data owner must, however, use a suitable identity‐based cryptographic mechanism to ensure the safety prerequisites while sharing data to large numbers of cloud data users with fuzzy identities. As a successful way to guarantee secure fuzzy sharing of cloud data, the identity‐based cryptographic technology still faces an effectiveness problem under multireceiver configurations. The chaos theory is considered a reasonable strategy for reducing computational complexity while meeting the cryptographic protocol's security needs. In an identity‐based cryptographic protocol, public keys for individual clients are distributed, allowing the clients to separately select their own network identities or names as their public keys. In fact, in a public‐key cryptographic protocol, it is for the best that the confirmation of the public key is done in a safe, private manner, because this way the load of storage on the server's side can be considerably relieved. The objective of this paper is to outline and examine a conversion process that can transfer cryptosystems using Chebyshev's chaotic maps over the Galois field to a subtree‐based protocol in the cloud computing setting for fuzzy user data sharing, as opposed to reconcocting a different structure. Furthermore, in the design of our conversion process, no adjustment of the original cryptosystem based on chaotic maps is needed.     

基于SDN的量子密码通信网络设计与研究

软件定义网络(SDN)采用OpenFlow技术分离网络设备的数据平面和控制平面,实现灵活控制网络资源的目的。基于此,设计了量子密码通信网络模型,实现灵活控制密码通信网络整体量子密匙资源,确保了信息的安全传输。此外,提出了综合到端可用密匙和跳数的路由算法,提高了QKD生成密匙的有效利用率。由测试结果可知,通过基于SDN的量子密码通信网络及路由算法,可提高量子密匙资源利用率,提高网络性能。     

一种安全芯片的访问控制设计

由于安全芯片承载了较多的敏感数据（如密钥）,因而其自身的安全也非常重要。对芯片内部的敏感数据进行安全地访问控制是增强其安全性的关键手段之一。提出了一种安全芯片的实施方案和敏感数据访问控制方法,采用软硬件协同配合实现。本方案增加硬件少,安全控制由软硬件配合完成;访问控制可以基于密码算法实现,也可以使用其它方式;访问控制方式可在生产与升级过程中更换,灵活性大。对安全芯片的设计具有较好的参考价值。     

A Multi-Pass True Motion Estimation Scheme With Motion Vector Propagation for Frame Rate Up-Conversion Applications

This paper presents a robust true motion estimation algorithm, designated as MPMVP (Multi-pass and Motion Vector Propagation), to enhance the accuracy of the motion vector fields in frame rate up-conversion applications. The MPMVP uses a multi-pass scheme to progressively refine approximate motion vectors to true motion vectors based upon the motion information acquired in previous passes. The multi-pass motion estimation process uses a large block size to detect the motion vectors within the objects themselves and small block sizes to detect the motion vectors along the object boundaries. Actually, the block size is progressively reduced during the search process. When the motion vector of a block is considered to be sufficiently accurate for motion estimation purposes, the block is said to be converged and the local motion vector search process terminates. A novel technique, referred to as motion vector propagation, is then applied to propagate the motion vector of the converged block to its neighboring blocks. This technique not only ensures that neighboring motion vectors within the same object have a high degree of spatial correlation, but also accelerates the convergence of the motion vectors in the neighboring blocks and therefore reduces the overall computational time and expense of the multi-pass motion vector search procedure. A novel distortion criterion is proposed to enhance the tolerance of the traditional sum-of-absolute-difference measurement technique applied in the motion estimation scheme to noise and shadow effects. The experimental results demonstrate that the proposed true motion estimation algorithm outperforms the traditional full search, 3DRS and TCSBP algorithms in terms of both the smoothness of the generated motion vector fields and the visual quality of the up-converted frames.     

基于分数阶Hilbert变换的多路加密

基于分数阶Hilbert变换的单边带通信可以同时将分数阶旋转角度作为加密密钥,从而保证通信安全。但基于分数阶Hilbert变换的单边带通信加密技术只能让信号使用一个加密密钥。为了达到增大密钥空间以更有效地保证信息安全的目的,采用多通道滤波器组分路处理的方法,在减少了系统计算复杂度的基础上增大了密钥空间。     

HMAC-SHA-256算法在TD-LTE系统中的应用

针对如何实现TD-LTE系统中根密钥KASME的计算,介绍了HMAC-SHA-256算法。该算法基于C语言实现,并在VS 2005环境下通过7组测试向量对算法的正确性与可靠性进行验证。最终,确定该算法用于TD-LTE系统根密钥的计算是可行的。     

Deadbeat control of a three-phase inverter with an output LC filter

The discrete-time control of a three-phase inverter with an output LC filter is described based on space vectors. The mathematical model of the inverter-filter system is first obtained by using space vectors to represent three-phase quantities. Deadbeat control laws are derived for no-load and resistive-load cases. Then, a deadbeat control law is obtained for the case when the load draws current of any waveshape from the inverter-filter. It is shown that deadbeat control of output voltage can be achieved in two control steps. The manipulated variable, which is the voltage vector demanded from the inverter, is implemented using the space vector modulation technique. Simulation results for various operating conditions are presented     

SINS/GPS/TACAN机载综合导航定位系统设计

在现代空战中,捷联惯性导航系统(SINS)、全球定位系统(GPS)和塔康(TACAN),单独利用各导航信息都存在着弊端.为此,提出了3种导航源综合的导航系统设计方案.信息融合技术采用广义联邦滤波技术来完成,状态矢量为导航参数误差,并建立准确数学模型.各个子滤波器(局部滤波器)采用间接滤波方式工作,完成状态矢量局部估算;...     

基于先验知识的支持向量机在图像分割中的应用研究

文中在研究现有先验知识与支持向量机融合的基础上,针对置信度函数凭经验给出的不足,提出了一种确定置信度函数方法,更好地进行分类。该方法是建立在模糊系统理论的基础上:将样本的紧密度信息作为先验知识应用于支持向量机的构造中,在确定样本的置信度时,不仅考虑了样本到所在类中心之间的距离,还考虑样本与类中其它样本之间的关系,通过模糊连接度将支持向量与含噪声样本进行区分。文中将基于先验知识的支持向量机应用于医学图像分割,以加拿大麦吉尔大学的brainWeb模拟脑部数据库提供的不同噪声的图像进行实验,实验结果表明采用基于先验知识的支持向量机比传统支持向量机具有更好的抗噪性能及分类能力。