结合全双工与协作干扰的无线网状网物理层安全策略

针对无线网状网中缺少窃听者先验知识不利场景中的安全连接问题,提出了一种结合全双工和协作干扰技术的物理层安全策略。利用全双工通信中的自干扰消除技术和协作干扰技术,提出的安全策略可有效劣化位于信息传播范围内包括潜伏在接收节点附近窃听者的接收性能。为保证信息的安全传输给出了协作干扰节点的选择方法,基于随机几何等数学方法导出了选定路径的安全连接概率表达式。性能分析和仿真结果表明,所提方法与仅基于全双工或协作干扰技术的方法相比,其安全性能有较大提升。     

NOMA系统中基于协作干扰的物理层安全方案

针对NOMA系统中的信息安全传输问题,提出基于协作干扰的物理层安全方案,该方案利用外部协作节点发送干扰信号恶化窃听者的接收性能。本文首先利用泊松点过程对协作节点和窃听者的位置进行安全建模,然后推导了随机协作干扰方案下系统保密中断概率的闭式解,但随机协作干扰方案会同时恶化合法用户的接收信号,性能有限,因此提出一种信道增益受限的协作干扰方案,该方案选择到近端用户和远端用户的瑞利信道因子均小于一定阈值的协作节点发送干扰信号,会对窃听者造成更严重的影响。仿真结果表明,在NOMA系统中采用受限的协作干扰方案能够有效提升系统安全性能。      

多跳协同中继网络下物理层安全传输方案

针对多跳中继传输系统的信息安全传输问题,提出了一种基于全双工模式下多节点协作干扰(FD-MCJ)的物理层安全传输方案。该方案利用通信网络中的中继节点发送干扰信号恶化窃听节点的接收性能,同时中继节点根据信道状态信息(Channel State Information, CSI)自适应的选择两种情况下的安全传输方案。本文首先利用泊松点过程对窃听节点位置进行安全建模;然后,根据CSI可用程度,给出不同的安全传输具体方案,在考虑系统的跳数、天线间自干扰以及发射功率和干扰功率等因素下,推导FD-MCJ方案下系统保密中断概率的闭式解;最后,数值分析和蒙特卡洛仿真表明,理论推导的正确性以及多跳中继系统中采用全双工多节点协作干扰方案能够有效提升系统安全性能。      

Exact Outage Probability of a Decode-and-Forward Scheme with Best Relay Selection Under Physical Layer Security

As demand for highly reliable data transmission in wireless networks has increased rapidly, cooperative communication technology has attracted a great deal of attention. In cooperative communication, some nodes, called eavesdroppers, illegally receive information that is intended for other communication links at the physical layer because of the broadcast characteristics of the wireless environment. Hence, Physical Layer Security is proposed to secure the communication link between two nodes against access by the eavesdroppers. In this paper, we propose and analyze the performance of decode-and-forward schemes with the best relay selection under Physical Layer Security with two operation protocols: first, only cooperative communication, and second, a combination of direct transmission and cooperative communication (the incremental protocol). In these schemes, a source transmits data to a destination with the assistance of relays, and the source-destination link is eavesdropped by one other node. The best relay is chosen in these proposals based on the maximum Signal-to-Noise ratio from the relays to the destination, and satisfies the secure communication conditions. The performance of each system is evaluated by the exact outage probability of the data rate over Rayleigh fading channels. Monte-Carlo results are presented to verify the theoretical analysis and are compared with a direct transmission scheme under Physical Layer Security and compared with each other.     

能量收集型高斯窃听信道安全速率的优化

针对无线网络存在安全威胁和能量受限的问题,该文研究了基于ST(Save-then-Transmit)协议的能量收集型高斯窃听信道的安全通信。首先,对系统安全速率最大化进行研究;其次,为进一步提高系统安全速率,给出了协作抗干扰方案,并讨论了该方案提高安全速率的充分必要条件,且提出了该方案下安全速率的迭代优化算法;最后,给出了一种复杂度低的单辅助端的选择方案。仿真结果表明,第1种优化方案明显提高了系统的安全速率;第2种协作抗干扰方案可进一步提高系统的安全速率且收敛速度较快;当原能量收集型高斯窃听信道不能进行安全通信时,协作抗干扰方案可在一定条件下实现安全传输。     

A New Relay and Jammer Selection Schemes for Secure One-Way Cooperative Networks

This paper presents different relay and jammer selection schemes for one-way cooperative networks to increase the security against malicious eavesdroppers. We consider a single source-destination cooperative network with multiple intermediate nodes and one or more eavesdroppers. The selection in the proposed schemes is made with the presence of direct links and the assumption that the broadcast phase is unsecured. The proposed schemes select three intermediate nodes. The first selected node operates in the conventional relay mode and assists the source to deliver its data to the corresponding destination via a Decode-and-Forward strategy. The second and third selected nodes are used in different communication phases as jammers to create intentional interference at the eavesdroppers’ nodes. Moreover, a hybrid scheme which switches between jamming and non-jamming modes is introduced in this paper. The proposed schemes are analyzed in terms of ergodic secrecy capacity and secrecy outage probability. Extensive analysis and a set of simulation results are presented to demonstrate the effectiveness of the different schemes presented in this work. The obtained results show that the proposed schemes with jamming outperform the conventional non-jamming schemes and the hybrid switching scheme further improves the secrecy capacity. The impact of changing both the eavesdroppers and the relays location on ergodic secrecy capacity and secrecy outage probability is also discussed. Finally, the impact of the presence of multiple eavesdroppers is studied in this paper.     

基于联盟博弈的多小区下行链路保密协作算法

考虑一个存在多窃听者的多小区下行链路蜂窝网络,协作小区通过在选定的子载波上执行协作波束赋形,利用小区间干扰抑制窃听者,实现安全传输。在窃听者位置未知的情况下,推导了下行链路保密连接概率的闭式表达式。在此基础上,将下行链路建模为博弈参与者,该文提出一种基于联盟博弈的多小区下行链路保密协作算法,以保密连接概率为效用函数,通过设计联盟加入和退出规则,实现了下行链路对子载波的高效选择和保密协作联盟的自组织生成。理论和仿真分析表明所提算法能够形成稳定的联盟结构,并且所提算法的保密性能优于传统的联盟协作算法。     

多用户选择与协作干扰的安全性能分析

研究了一种多用户选择与协作干扰相结合的无线传输模型。在Nakagami-m衰落信道下，考虑到信道中的反馈延迟对信道状态信息的影响，采用合法信道的过时信道状态信息来选择目的用户。采用一般次序选择策略选择目的用户，并结合噪声干扰策略进行干扰，实现信息的安全传输。针对窃听信道两种不同信道状态信息，分别推导了中断概率和窃听概率的准确闭合表达式，并给出二者性能折中的表达式。理论分析与数值仿真表明，减小用户选择参数以及降低信道衰落参数能够有效地改善系统的可靠性与安全性折中安全性能。      

有限字符输入系统的物理层安全传输条件

针对无线数字通信系统中人工噪声方法可被多天线窃听者破解的问题,该文提出有限字符输入下物理层安全传输的一个充分条件,并以此为指导设计了一种类符号人工噪声方法。分析表明,人工噪声方法下,有限字符输入信号和窃听者无噪接收信号之间的等效信道是一个离散有噪无损信道(Discrete Noisy Lossless Channel, DNLC)。由于DNLC输入信号的可逆性为窃密提供了必要条件,窃听者通过增加天线可使窃听信道容量达到合法用户的信道容量上限,致使系统的保密互信息为零,因此破坏输入信号的可逆性是有限字符输入下物理层安全传输的一个充分条件。类符号人工噪声方法满足这一充分条件,可以保证物理层安全传输,仿真结果也表明了该方法的有效性。     

一种基于扩展GHZ态的改进量子“乒乓”协议

In order to transmit secure messages, a quantum secure direct communication protocol based on extended three-particle GHZ state was presented, in which the extended three-particle GHZ state was used to detect eave sdroppers . In the security analysis, the method of the entropy theory is introduced, and three detection strategies are compared quantitatively by using the constraint between the information eavesdroppers can obtain and the interference introduced. If the eavesdroppers intend to obtain all information, the detection rate of the original "Ping-pong" protocol is 50% ; the second protocol used two particles of EPR pair as detection particles is also 50% ; while the presented protocol is 58% . At last, the security of the proposed protocol is discussed. The analysis results indicate that the protocol in this paper is more secure than the other two.     

基于连通图的动态可重构多机协同干扰方法

针对多机空战电子对抗中,干扰目标分配和协同干扰资源选择问题,在分析空战有源电子干扰面临复杂电磁环境、雷达跟踪干扰源、干扰目标分配和干扰资源选择等问题的基础上,建立双机协同干扰数学模型,分析协同干扰对测角误差影响因素,提出基于连通图的动态可重构双机协同干扰方法,并应用于典型的“磨刀匠”攻击战术。仿真结果表明,基于连通图的动态可重构双机协同干扰方法,能够实现多机编队协同作战时的最优协同干扰资源和干扰目标选择,实现对单脉冲机载火控雷达协同角度欺骗干扰,且算法计算时间完全符合协同干扰需求,为新型战斗机协同干扰提供了借鉴。     

提高随机网络安全的干扰协调方法(英文)

The co-channel interference modeling is vital for evaluating the secrecy performance in random wireless networks,where the legitimate nodes and eavesdroppers are randomly distributed.In this paper,a new interference model is proposed from the userdominant perspective.The model can provide a better analytical assessment of secrecy performance with interference coordination for the presence of eavesdroppers.The typical legitimate is assumed to be located at the origin,and chooses the closest base station(BS) as its serving BS.The field of interferers is obtained by excluding the desired BSs(including the serving BS and its cooperative BS(s)).In contract with the exiting interference model,it is assumed that desired BSs and interferers belong to the same Poisson Point Process(PPP),and eavesdroppers are distributed according to another independent PPP.Based on this model,the average secrecy transmission capacity is derived in simply analytical forms with interference coordination.Analysis and simulation results show that the secrecy performance can be significantly enhanced by exploiting interference coordination.Furthermore,the average secrecy transmission capacity increases with increasing number of cooperative BSs.     

Partial encryption of compressed images and videos

The increased popularity of multimedia applications places a great demand on efficient data storage and transmission techniques. Network communication, especially over a wireless network, can easily be intercepted and must be protected from eavesdroppers. Unfortunately, encryption and decryption are slow, and it is often difficult, if not impossible, to carry out real-time secure image and video communication and processing. Methods have been proposed to combine compression and encryption together to reduce the overall processing time, but they are either insecure or too computationally intensive. We propose a novel solution called partial encryption, in which a secure encryption algorithm is used to encrypt only part of the compressed data. Partial encryption is applied to several image and video compression algorithms in this paper. Only 13-27% of the output from quadtree compression algorithms is encrypted for typical images, and less than 2% is encrypted for 512×512 images compressed by the set partitioning in hierarchical trees (SPIHT) algorithm. The results are similar for video compression, resulting in a significant reduction in encryption and decryption time. The proposed partial encryption schemes are fast, secure, and do not reduce the compression performance of the underlying compression algorithm     

基于接收机人工噪声的物理层安全技术及保密区域分析

提出了一种实现无线通信物理层安全的新方法,并从信息论的角度进行了性能分析。此方法通过合法接收者发送人工噪声来干扰窃听者信道,同时通过抵消技术使得自身不受人工噪声的影响。此方法无需信道信息的反馈,能够对抗多天线的窃听者,具有强的鲁棒性。此外基于地理位置信息提出了一种“保密区域”的新概念,可以作为物理层安全的评价标准和设计准则。分析和仿真结果表明所提算法对安全性能的提升较为明显,所提“保密区域”概念能够较好的从地理位置的角度评估物理层安全性能。      

Reliable and Secure Cooperative Communication for Wireless Sensor Networks Making Use of Cooperative Jamming with Physical Layer Security

Interference is generally considered as the redundant and unwanted occurrence in wireless communication. This research work proposes a novel cooperative jamming mechanism for scalable networks like wireless sensor networks which makes use of friendly interference to confuse the eavesdropper and increase its uncertainty about the source message. The communication link is built with the help of Information theoretic source and channel coding mechanisms. The whole idea is to make use of normally inactive relay nodes in the selective Decode and Forward cooperative communication and let them work as cooperative jamming sources to increase the equivocation of the eavesdropper. In this work, eavesdropper’s equivocation is compared with the main channel in terms of mutual information and secrecy capacity.     

Friendship-based cooperative jamming for secure communication in Poisson networks

This paper investigates the physical layer security-based secure communication in a finite Poisson network with social friendships among nodes, for which a social friendship-based cooperative jamming scheme is proposed. The jamming scheme consists of a Local Friendship Circle (LFC) and a Long-range Friendship Annulus (LFA), where all legitimate nodes in the LFC serve as jammers, but the legitimate nodes in the LFA are selected as jammers through three location-based policies. To understand both the security and reliability performances of the proposed scheme, we first derive analytical expressions for the transmission outage probability and determine both the upper and lower bounds on the secrecy outage probability, given the basic Laplace transform of the sum interference at any location in the network. With the help of the tools from stochastic geometry, we then provide general expressions for the above Laplace transform under all path loss scenarios as well as closed-form Laplace transform results under two typical path loss cases, such that the overall outage performances of the proposed scheme can be depicted. Finally, we present extensive numerical results to validate our theoretical analysis and also to illustrate the impacts of the friendship-based cooperative jamming on the network performances.

     

能量收集系统中基于能量协同和协同干扰的保密传输方案

研究节点具备能量收集能力的中继窃听信道保密速率的优化问题,提出一种基于人工噪声协同干扰和节点间能量协同的物理层安全传输策略.各节点采用储能-发送模式工作,即先收集能量,再用于数据传输.中继节点采用放大转发方式,目的节点发送人工噪声进行协同干扰.由于中继节点所需功耗较高,目的节点将用于发送干扰之外的剩余能量转移给中继节点.给出以最大化保密速率为目标函数,优化能量吸收时间比例系数和干扰功率分配因子的两步优化算法.仿真结果表明人工噪声和能量协同的引入能有效提高系统的保密传输速率.     

Optimization Schemes for Protective Jamming

In this paper, we study strategies for allocating and managing friendly jammers, so as to create virtual barriers that would prevent hostile eavesdroppers from tapping sensitive wireless communication. Our scheme precludes the use of any encryption technique. Applications include domains such as (i) protecting the privacy of storage locations where RFID tags are used for item identification, (ii) secure reading of RFID tags embedded in credit cards, (iii) protecting data transmitted through wireless networks, sensor networks, etc. By carefully managing jammers to produce noise, we show how to reduce the SINR of eavesdroppers to below a threshold for successful reception, without jeopardizing network performance. In this paper, we present algorithms targeted towards optimizing power consumption and number of jammers needed in several settings. Experimental simulations back up our results.     

Cooperative Physical Layer Security Transmission Scheme Based on Energy Harvesting

Energy harvesting (EH) is introduced into the physical layer security transmission of wireless sensor networks. It takes the energy efficiency and security into account simultaneously. To improve the physical layer security of the cooperative wireless sensor network, an EH-based physical layer security transmission scheme called multi-relay time switching (MRTS) is proposed in this paper. In the multi-source single-destination network with eavesdroppers, multiple relay nodes with time switching (TS) protocol convert the received signals into energy and information according to the time slots, and the converted energy is used to amplify and forward the received information. The research shows the optimal time switching ratio, under which the maximum secrecy capacity is achievable with the optimal converted energy. The results prove that under the same conditions, the secure transmission scheme based on MRTS is better than power splitting-based relaying (PSR) scheme when the total power of sources is limited.

     

智能窃听下协作NOMA网络的性能分析

针对下行双用户NOMA (Non-Orthogonal Multiple Access)系统模型中存在智能窃听者,该窃听者可以自适应地选择被动窃听或主动干扰工作模式,在不精确了解其干扰水平的情况下,部分NOMA用户很有可能遭遇传输质量下降乃至保密中断,这将对信息安全传输构成严重威胁。另外,由于信道衰落,用户的位置对系统整体性能有很大影响,难以保证距离源节点较远用户的传输质量。为解决上述问题,本文提出了一种新型的两阶段用户协作方案。第一阶段,远用户采用全双工(full-duplex,FD)干扰智能窃听者,第二阶段,近用户可作为一个中继协助源节点转发远用户信号信息,并在接收端采用串行干扰消除（Successive Interference Cancellation, SIC）技术进行解码。使用户间达成合作,提高通信链路安全性和用户服务质量。考虑到系统中不同用户的信息接收速率与通信需求不同之间的相关性,分别推导了遍历安全容量和遍历容量的解析表达式,同时分析了功率分配因子和用户间协作发射功率等因素对性能的影响,并通过Monte-Carlo仿真验证了其正确性。