Attack Detection for Spoofed Synchrophasor Measurements Using Segmentation Network

Synchrophasor measurements are essential to realtime situational awareness of the smart grid but vulnerable to cyber-attacks during the process of transmission and invocation.To ensure data security and mitigate the impact of spoofed synchrophasor measurements,this work proposes a novel object detection method using a Weight-based One-dimensional Convolutional Segmentation Network(WOCSN)with the ability of attack behavior identification and time localization.In WOCSN,automatic data feature extraction can be achieved by onedimensional convolution from the input signal,thereby reducing the impact of handcrafted features.A weight loss function is designed to distribute the contribution for normal and attack signals.Then,attack time is located via the proposed binary method based on pixel segmentation.Furthermore,the actual synchrophasor data collected from four locations are used for the performance evaluation of the WOCSN.Finally,combined with designed evaluation metrics,the time localization ability of WOCSN is validated in the scenarios of composite attacks with different spoofed intensities and time-sensitivities.

Modified Cepstral Feature for Speech Anti-spoofing

The hidden danger of the automatic speaker verification(ASV)system is various spoofed speeches.These threats can be classified into two categories,namely logical access(LA)and physical access(PA).To improve identification capability of spoofed speech detection,this paper considers the research on features.Firstly,following the idea of modifying the constant-Q-based features,this work considered adding variance or mean to the constant-Q-based cepstral domain to obtain good performance.Secondly,linear frequency cepstral coefficients(LFCCs)performed comparably with constant-Q-based features.Finally,we proposed linear frequency variance-based cepstral coefficients(LVCCs)and linear frequency mean-based cepstral coefficients(LMCCs)for identification of speech spoofing.LVCCs and LMCCs could be attained by adding the frame variance or the mean to the log magnitude spectrum based on LFCC features.The proposed novel features were evaluated on ASVspoof 2019 datase.The experimental results show that compared with known hand-crafted features,LVCCs and LMCCs are more effective in resisting spoofed speech attack.

Enforcing a Source-end Cooperative Multilevel Defense Mechanism to Counter Flooding Attack

The exponential advancement in telecommunication embeds the Internet in every aspect of communication.Interconnections of networks all over the world impose monumental risks on the Internet.A Flooding Attack(FA)is one of the major intimidating risks on the Internet where legitimate users are prevented from accessing network services.Irrespective of the protective measures incorporated in the communication infrastructure,FA still persists due to the lack of global cooperation.Most of the existing mitigation is set up either at the traffic starting point or at the traffic ending point.Providing mitigation at one or the other end may not be a complete solution.To insist on better protection againstflooding attacks,this work proposes a cooperative multilevel defense mechanism.The proposed cooperative multilevel defense mechanism consists of two-level of mitigation.In thefirst level,it is proposed to design a Threshold-based rate-limiting with a Spoofing Resistant Tag(TSRT),as a source end countermeasure for High-Rate Flooding Attacks(HRFA)and spoofing attacks.In the second level,the accent is to discriminate normal traffic after Distributed Denial of Service(DDoS)traffic and drop the DDoS traffic at the destination end.Flow Congruence-based Selective Pushback(FCSP),as a destination-initiated countermeasure for the Low Rate Flooding Attack(LRFA).The source and the destination cooperate to identify and block the attack.A key advantage of this cooperative mechanism is that it can distinguish and channel down the attack traffic nearer to the starting point of the attack.The presentation of the agreeable cooperative multilevel safeguard mechanism is approved through broad recreation in NS-2.The investigation and the exploratory outcomes show that the proposed plan can effectively identify and shield from the attack.

卫星链路中TCP传输性能改进与仿真

卫星信道与地面有线信道具有不同的特点,当TCP协议直接应用于卫星链路上时,其吞吐量等性能会受到影响。针对卫星链路的特点,分析了现有的卫星链路进行TCP传输的几种解决方案,使用NS 2仿真软件,建立了仿真模型,并在给定的仿真环境下得出了一些卫星链路下TCP传输性能和卫星spoofing技术的仿真结论。卫星链路具有时延大、误码率高等特点,仿真结果说明卫星spoofing技术和PS技术相结合的方案对卫星链路TCP传输性能改善是十分有益的。

一种基于Intranet的分布式IP Spoof检测系统

提出了基于Intranet的分布式IPSpoof检测系统。该系统能高效检测Intranet内的IPSpoof行为。分析了目前的IPSpoof防范技术。根据Intranet的特点详细介绍了系统的设计。给出了IPSpoof判定方法、检测系统的关键部件Monitor的设计,并给出了数据采集模块的实现。实验表明,该系统具备高精度、高实时性和低流量的特点,可以在不同规模的Intranet以及网络安全系统中广泛使用。

TSLV：基于时间切片的车载网络位置验证方法(英文)

Position-spoofing-based attacks seriously threaten the security of Vehicular Ad Hoc Network(VANET).An effective solution to detect position spoofing is location verification.However,since vehicles move fast and the topology changes quickly in VANET,the static location verification method in Wireless Sensor Network(WSN) is not suitable for VANET.Taking into account the dynamic changing topology of VANET and collusion,we propose a Time-Slice-based Location Verification scheme,named TSLV,to resist position spoofing in VANET.Specifically,TSLV transforms the dynamic topology into static topology by time slice and each time slice corresponds to a verification process.The verifier can implement location verification for the corresponding prover.During the verification process,the verifier first filters out vehicles which provide unreasonably claimed locations,and then uses the Mean Square Error(MSE)-based cluster approach to separate the consistent vehicles by time slice,and uses the consistent set for its verification.In addition,security analysis and simulation show that TSLV can defend against the collusion attack effectively.

Spoof surface plasmon-based bandpass filter with extremely wide upper stopband

We investigate the guiding modes of spoof surface plasmon polaritons （SPPs） on a symmetric ultra-thin plasmonic structure. From the analysis, we deduce the operating frequency region of the single-mode propagation. Based on this property, a spoof SPPs lowpass filter is then constituted in the microwave frequency. By introducing a transmission zero at the lower frequency band using a pair of stepped-impedance stubs, a wide passband filter is further realized. The proposed filter is fed by.a transducer composed of a microstrip line with a flaring ground. The simulated results show that the presented filter has an extremely wide upper stopband in addition to excellent passband filtering characteristics such as low loss, wide band, and high square ratio. A prototype passband filter is also fabricated to validate the predicted performances. The proposed spoof-SPPs filter is believed to be very promising for other surface waveguide components in microwave and terahertz bands.

基于TCP/IP协议应用层漏洞的网络攻击分析

近年来,计算机和网络技术在全世界范围内得到迅猛发展和广泛应用,网络应用已经深入人们日常生活的各个方面。人类充分享受到了网络给工作和生活带来的巨大便利。但是另一方面,由于计算机系统和网络系统仍处于不断发展中,其本身还存在大量的漏洞,也使得越来越多的网络安全问题开始出现。本文将在分析TCP/IP协议应用层常见应用的基础上重点探讨基于telnet、Web Spoofing以及FTP Bouncing三种最常见的网络漏洞攻击。

Improved adaptively robust estimation algorithm for GNSS spoofer considering continuous observation error

Once the spoofer has controlled the navigation sys-tem of unmanned aerial vehicle(UAV),it is hard to effectively control the error convergence to meet the threshold condition only by adjusting parameters of estimation if estimation of the spoofer on UAV has continuous observation error.Aiming at this problem,the influence of the spoofer’s state estimation error on spoofing effect and error convergence conditions is theoretically analyzed,and an improved adaptively robust estimation algo-rithm suitable for steady-state linear quadratic estimator is pro-posed.It enables the spoofer’s estimator to reliably estimate UAV status in real time,improves the robustness of the estima-tor in responding to observation errors,and accelerates the con-vergence time of error control.Simulation experiments show that the mean value of normalized innovation squared(NIS)is reduced by 88.5%,and the convergence time of NIS value is reduced by 76.3%,the convergence time of true trajectory error of UAV is reduced by 42.3%,the convergence time of estimated trajectory error of UAV is reduced by 67.4%,the convergence time of estimated trajectory error of the spoofer is reduced by 33.7%,and the convergence time of broadcast trajectory error of the spoofer is reduced by 54.8%when the improved algorithm is used.The improved algorithm can make UAV deviate from pre-set trajectory to spoofing trajectory more effectively and more subtly.

Spoof surface plasmon polaritons excited leaky-wave antenna with continuous scanning range from endfire to forward

A novel leaky-wave antenna(LWA)utilizing spoof surface plasmon polaritons(SSPPs)excitation is proposed with continuous scanning range from endfire to forward.The designed transmission line unit supports two SSPPS modes,of which the 2nd order mode is applied in the design.A novel strategy has been devised to excite the spatial radiation of the-1st order harmonics by arranging periodic counter changed sinusoidal structures on both sides of the SSPPs transmission line.Both full-wave simulation and measurement results show that the proposed LWA presents wide scanning angle from endfire to forward.In the frequency range from 4 GHz to 10 GHz,LWAs achieve scanning from 90°to+20°,covering the entire backward quadrant continuously.

Evaluation of global navigation satellite system spoofing efficacy

The spoofing capability of Global Navigation Satellite System(GNSS)represents an important confrontational capability for navigation security,and the success of planned missions may depend on the effective evaluation of spoofing capability.However,current evaluation systems face challenges arising from the irrationality of previous weighting methods,inapplicability of the conventional multi-attribute decision-making method and uncertainty existing in evaluation.To solve these difficulties,considering the validity of the obtained results,an evaluation method based on the game aggregated weight model and a joint approach involving the grey relational analysis and technique for order preference by similarity to an ideal solution(GRA-TOPSIS)are firstly proposed to determine the optimal scheme.Static and dynamic evaluation results under different schemes are then obtained via a fuzzy comprehensive assessment and an improved dynamic game method,to prioritize the deceptive efficacy of the equipment accurately and make pointed improvement for its core performance.The use of judging indicators,including Spearman rank correlation coefficient and so on,combined with obtained evaluation results,demonstrates the superiority of the proposed method and the optimal scheme by the horizontal comparison of different methods and vertical comparison of evaluation results.Finally,the results of field measurements and simulation tests show that the proposed method can better overcome the difficulties of existing methods and realize the effective evaluation.

几种常见网络攻击的方法与对策研究

随着计算机网络的普及和发展,我们的生活和工作都越来越依赖于网络,与此相关的网络安全问题也随之凸现出来。论文分析并探讨了一般性的网络攻击原理和手段,其中对IP Spoofing攻击方法和SYNF looding作了详尽的讨论,最后提出了未来网络攻击方式演变的四种可能攻击趋势。

融合MobileNet与GhostVLAD的欺骗语音检测

欺骗语音已经对自动说话人识别系统产生严重影响。语音转换、语音合成和语音重放是对ASV系统进行欺骗的3种主要手段,但流行的欺骗检测方法使用的卷积神经网络大多层数较深、网络较复杂,不适合在移动设备以及嵌入式设备上运行。针对这一问题,提出一种适用于3种欺骗情况下的基于轻量型神经网络Mo⁃bileNet和GhostVLAD(Ghost Vector of Local Aggregated Descriptors)方法相结合的算法。首先对语音数据进行增广并提取常数Q倒谱系数和振幅频谱图,将其作为输入特征;然后将MobileNetV2或V3-large网络的最后一个池化层替换为GhostVLAD聚合层;最后使用端到端的优化方法对真实语音和欺骗语音进行识别。在ASVspoof 2019数据集上进行实验,结果表明该算法效果较好,相比基线系统在等错误率上分别降低了38%和13%。

A Secure Interaction and Control Method for InterClouds Services

Inter-clouds services build information bridges over computing clouds so as to provide the convenience for electronic commerce and other information services. However, the interactions between clouds have challenges in information disclosure, services spoofing and information inconsistent. This paper proposes a secure interaction and control method for inter-clouds services, which uses information encryption, digital signature,time logic control means, to protect users' privacy and keep the integrity and consistency of cloud customers' request information, and prevent the spoofing of information requests. The results show that the method could prevent the spoofing well in a stable network environment and improve the security of clouds sessions.

Negative-index dispersion and accidental mode degeneracy in an asymmetric spoof-insulator-spoof waveguide

It has been recently demonstrated that negative-index dispersion and mode degeneracy can be achieved by manipulating a spoof-insulator-spoof（SIS） waveguide. In this paper, we propose a new SIS waveguide, which is composed of two spoof surface plasmon polaritons（SSPPs） waveguides drilled with periodic rhomboidal grooves. Both the symmetric and asymmetric cases are investigated. Our simulation results show that the asymmetric SIS waveguides are more significant.By tailoring the tilt of the rhomboidal grooves, the negative-index dispersion can be achieved and the microwave band gap（MBG） can be effectively modulated. At a critical tilt, there appears an accidental mode degeneracy at the edge of the first Brillouin zone. The excitation and propagation of the two coupled modes sustained by the asymmetric SIS waveguides are also demonstrated.

Design and verification of a broadband highly-efficient plasmonic circulator

Circulators play a significant role in radar and microwave communication systems.This paper proposes a broadband and highly efficient plasmonic circulator,which consists of spoof surface plasmon polaritons(SSPPs)waveguides and ferrite disks to support non-reciprocal mode coupling.The simulated performance of symmetrically designed circulator shows that it has an insertion loss of roughly 0.5 dB while the isolation and return loss is more than 12 dB in the frequency range of 6.0 GHz–10.0 GHz(relative bandwidth of 50%).Equivalent circuit model has been proposed to explain the operating mechanism of the plasmonic circulator.The equivalent circuit model,numerical simulations,and experimental results are consistent with each other,which demonstrates the good performance of the proposed plasmonic circulator.

GPS Spoofing Attack Detection in Smart Grids Based on Improved CapsNet

This paper analyzes the influence of the global positionong system(GPS)spoofing attack(GSA)on phasor measurement units(PMU)measurements.We propose a detection method based on improved Capsule Neural Network(CapsNet)to handle this attack.In the improved CapsNet,the gated recurrent unit(GRU)is added to the front of the full connection layer of the CapsNet.The improved CapsNet trains and updates the network parameters according to the historical measurements of the smart grid.The detection method uses different structures to extract the temporal and spatial features of the measurements simultaneously,which can accurately distinguish the attacked data from the normal data,to improve the detection accuracy.Finally,simulation experiments are carried out on IEEE 14-,IEEE 118-bus systems.The experimental results show that compared with other detection methods,our method is proved to be more efficient.

High-confinement ultra-wideband bandpass filter using compact folded slotline spoof surface plasmon polaritons

A novel bandpass filter(BPF)based on spoof surface plasmon polaritons(SSPPs)using a compact folded slotline structure is proposed and experimentally demonstrated.The proposed novel SSPPs structure compared with a conventional plasmonic waveguide with slot line SSPPs unit structure at the same size,the considerable advantages in much lower asymptotic frequency with tight field confinement,which enable the proposed filter to be more miniaturization.A high-efficient mode conversion structure is designed to transition from TE-mode to SSPPs-mode by gradient slotline lengths.The low-frequency stop-band can be committed with microstrip to slotline evolution on both sides of the dielectric,while the high-frequency cutoff band is realized by the proposed SSPPs structure.The influence of dispersion relation,electric field distribution,surface current,and structural parameters on the transmission characteristics of the proposed BPF are analyzed by finite difference time domain(FDTD).To validate the design concept,the prototype of the miniaturized SSPPs BPF has been manufactured and measured.The experimental results show high performance of the fabricated sample,in which the working in a range of 0.9 GHz-5.2 GHz with the relative bandwidth is 142%,the insertion loss less than 0.5 dB,the reflection coefficient less than-10 dB,and the group delay is less than one ns.This works provides a mirror for realizing the miniaturization of waveguides,and the application and development of high-confinement SSPPs functional devices in the microwave and THz regimes.

Active odd-mode-metachannel for single-conductor systems

Although tremendous efforts have been devoted to investigating planar single-conductor circuits,it remains challenging to provide tight confinement of electromagnetic field and compatibility with active semi-conductor components such as amplifier,harmonic generator and mixers.Single-conductor spoof surface plasmon polariton(SSPP)structure,which is one of the most promising planar single-conductor transmission media due to the outstanding field confinement,still suf-fers from the difficulty in integrating with the active semi-conductor components.In this paper,a new kind of odd-mode-metachannel(OMM)that can support odd-mode SSPPs is proposed to perform as the fundamental transmission chan-nel of the single-conductor systems.By introducing zigzag decoration,the OMM can strengthen the field confinement and broaden the bandwidth of odd-mode SSPPs simultaneously.More importantly,the active semi-conductor amplifier chip integration is achieved by utilizing the intrinsic potential difference on OMM,which breaks the major obstacle in im-plementing the single-conductor systems.As an instance,an amplifier is successfully integrated on the single-conductor OMM,which can realize both loss compensation and signal amplification.Meanwhile,the merits of OMM including crosstalk suppression,low radar cross section(RCS),and flexibility are comprehensively demonstrated.Hence,the pro-posed OMM and its capability to integrate with the active semi-conductor components may provide a new avenue to fu-ture single-conductor conformal systems and smart skins.

Switchable directional scattering based on spoof core-shell plasmonic structures

Manipulating directional electromagnetic scattering plays a crucial role in the realization of exotic optical phenomenon.Here,we show that the spoof plasmonic structure is able to achieve the switching of directional scattering direction on a subwavelength scale by inserting a perfect electric conductor(PEC)cylinder into the hollow of the spoof plasmonic structure.Based on the modal analysis,it is found that the electromagnetic response of the core-shell structure not only is well excited,but also exhibits the directional scattering by interference between the electric and magnetic dipolar resonances.We also discuss the influence of PEC cylinder radius on the performance of the directional scattering.Finally,the active tunable directional scattering is realized by switching between the two states.This work provides a feasible pathway to the subwavelength manipulation of electromagnetic wave.Moreover,it offers a simple method to switch the directional scattering direction.The proposed design approach can be easily applied to digital electromagnetic wave communication and associated applications.