多密钥加密方法设计

为了提高信息传输过程中的安全性,对当前的加密方法进行了研究,并介绍了通过对密钥进行处理增加加密安全性的研究现状。根据数据在发送和加密过程中要进行分段和分组的原理,设计了一种多密钥加密的方法：由源密钥和随机数生成分段密钥组和分组密钥组,由序号按匹配算法为每个分段和分组的数据选取相应密钥,实现多个密钥对信息传输过程中的加密。最后,一方面通过MATLAB测试验证该方法的加密效率,另一方面从理论和数学角度分析该方法的安全性并和传统方法进行对比,得到结论：该方法不需要太多开销即可在传统方法的基础上增加安全性。     

Markov微分博弈模型及其在网络安全中的应用

当前基于博弈理论的网络安全研究成果难以应用于实时、连续、随机对抗的网络攻防过程.本文针对网络安全防御的实时性和网络状态变化的随机性,基于动态、实时对抗的视角分析攻防行为,在结合微分博弈模型和Markov决策方法的基础上进行扩展,构建Markov攻防微分博弈模型,分析具有多个阶段且每阶段持续时间较短的攻防过程;提出多阶段博弈均衡解计算方法,设计多阶段最优防御策略选取算法.仿真实验结果表明,模型和算法有效且可行.     

Provably secure rational delegation computation protocol

A provably secure rational delegation computation scheme was proposed to solve the requirement of security issues in rational delegate computation.Firstly,game theory was introduced into delegation computation and according to rational participants behavior preferences analysis,a rational delegate computing game model was designed.Secondly,according to the equilibrium demand of game model and the security requirement of rational delegation computation,a rational security model was established.Thirdly,combining Yao's garbled circuit with its advantages of re-randomization,as well as full homomorphic encryption technology,the rational delegation computation protocol was constructed.And the combination of strategies in the protocol could reach the Nash equilibrium state.Finally,the security of the protocol and the privacy of the input and output were proved according to the rational security model,and the performance analysis shows the validity of the protocol.The proposed rational delegation computing protocol not only satisfies the traditional security,but also considers the behavioral preference of participants,which is more in line with the delegationcomputing mode under the big data environment.     

Physical layer security performance analysis of multi-antenna full-duplex relay aided heterogeneous cellular network

To alleviate the spectrum shortage problem and security threats in heterogeneous network (HetNet),multi-antenna full-duplex relay was introduced for communication between femto base station (FBS) and legitimate user.With the aid of multi-antenna full-duplex relay in FBS network,the secrecy performance of HetNets could be improved.Under a stochastic geometry framework,the fundamental analysis model to evaluate the secrecy performance in multi-antenna full-duplex relay aided HetNet was set up.To be specific,the exact expressions for the secrecy outage probability of the typical user,serving relays and HetNet were derived respectively.Then,based on the theoretical analyses and simulation results,the influences of transmit power and antenna number of both macro base station and FBS on secrecy performance in HetNet were examined.Finally,the results show that introducing multi-antenna full-duplex relay for FBS networks improves the secrecy performance of HetNet.     

Cooperative interference power allocation in physical layer security under imperfect time synchronization

In physical layer security,considering imperfect time synchronization,a power allocation scheme was proposed to maximize the system secrecy capacity.By analyzing the residual interference power at the authorized receiver caused by imperfect time synchronization,the optimal power distribution method was given,and the relationship between the optimal interference power and the relative channel quality was discussed.Theory and simulation analysis show that when the synchronization error is small,the synchronization error consumes extra power to reach the preset secrecy capacity,and the interference power increases with its increase.As the synchronization error increases,the secrecy capacity of the system gradually fails to reach the preset target,and may even drop to zero.     

基于红外视频的加油枪油气泄漏检测方法

加油站如果发生油气泄漏将造成巨大危害。针对加油枪泄漏油气具有的浓度低、动态发展等特性,提出一种基于红外视频的加油枪油气泄漏检测方法:利用红外相机采集加油枪工作区域的视频信号,针对其建立混合高斯背景模型,联合帧差法和背景消除法得到疑似泄漏图像;对该图像进行形态学和滤波运算,提取帧图像的形状和扩散特征,根据油气泄漏的特征范围,消除信号噪声干扰;建立图像灰度与油气浓度间的映射方程,按照国家油气泄漏浓度标准的相关规定,判断是否泄漏超标。本研究以水蒸气为模拟实验对象进行测试,结果表明该方法能较为精准的判断泄漏情况。     

FPGA-based Physical Unclonable Functions: A comprehensive overview of theory and architectures

Physically Unclonable Functions (PUFs) are a promising technology and have been proposed as central building blocks in many cryptographic protocols and security architectures. Among other uses, PUFs enable chip identifier/authentication, secret key generation/storage, seed for a random number generator and Intellectual Property (IP) protection. Field Programmable Gate Arrays (FPGAs) are re-configurable hardware systems which have emerged as an interesting trade-off between the versatility of standard microprocessors and the efficiency of Application Specific Integrated Circuits (ASICs). In FPGA devices, PUFs may be instantiated directly from FPGA fabric components in order to exploit the propagation delay differences of signals caused by manufacturing process variations. PUF technology can protect the individual FPGA IP cores with less overhead. In this article, we first provide an extensive survey on the current state-of-the-art of FPGA based PUFs. Then, we provide a detailed performance evaluation result for several FPGA based PUF designs and their comparisons. Subsequently, we briefly report on some of the known attacks on FPGA based PUFs and the corresponding countermeasures. Finally, we conclude with a brief overview of the FPGA based PUF application scenarios and future research directions.     

HP-VCS: A high-quality and printer-friendly visual cryptography scheme

Visual Cryptography Scheme (VCS) is a secret-sharing scheme which aims to encrypt a secret message into multiple shares and transmit them to participants over an untrusted communication channel. Although human vision can easily reveal the secret message by stacking a sufficient number of shares, this scheme reduces the visual quality of recovered images. This paper presents a novel high-quality and printer-friendly VCS. When providing high-quality recovery, this scheme keeps the size of the shares the same as the secret image. Experimental results show that, compared with previous work, the proposed scheme significantly improves the performance of recovered images.     

Laser-Empowered Random Metasurfaces for White Light Printed Image Multiplexing

Printed image multiplexing based on the design of metasurfaces has attracted much interest in the past decade. Optical switching between different images displayed directly on the metasurface is performed by altering the parameters of the incident light such as polarization, wavelength, or incidence angle. When using white light, only two-image multiplexing is implemented with polarization switching. Such metasurfaces are made of nanostructures perfectly controlled individually, which provide high-resolution pixels but small images and involve long fabrication processes. Here, it is demonstrated that laser processing of nanocomposites offers a versatile low-cost, high-speed method with large area processing capabilities for controlling the statistical properties of random metasurfaces, allowing up to three-image multiplexing under white light illumination. By independently controlling absorption and interference effects, colors in reflection and transmission can be varied independently yielding two-image multiplexing under white light. Using anisotropy of plasmonic nanoparticles, a third image can be multiplexed and revealed through polarization changes. The design strategy, the fundamental properties, and the versatility of implementation of these laser-empowered random metasurfaces are discussed. The technique, applied on flexible substrate, can find applications in information encryption or functional switchable optical devices, and offers many advantages for visual security and anticounterfeiting.     

基于大数据环境下网络安全相关问题探索

大数据网络和互联网平台、物联网平台、计算机技术等存在紧密联系,大数据环境为人们正常生产和生活提供了便利,也带来一些网络安全问题。在大数据背景下,需要重点分析网络安全相关问题,强化安全技术的研究力度,借助先进技术提升网络安全性,为大数据环境下的网络系统良好运行发展夯实基础。