41 research outputs found

    TORKAMELEON. IMPROVING TOR’S CENSORSHIP RESISTANCE WITH K-ANONYMIZATION MEDIA MORPHING COVERT INPUT CHANNELS

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    Anonymity networks such as Tor and other related tools are powerful means of increas- ing the anonymity and privacy of Internet users’ communications. Tor is currently the most widely used solution by whistleblowers to disclose confidential information and denounce censorship measures, including violations of civil rights, freedom of expres- sion, or guarantees of free access to information. However, recent research studies have shown that Tor is vulnerable to so-called powerful correlation attacks carried out by global adversaries or collaborative Internet censorship parties. In the Tor ”arms race” scenario, we can see that as new censorship, surveillance, and deep correlation tools have been researched, new, improved solutions for preserving anonymity have also emerged. In recent research proposals, unobservable encapsulation of IP packets in covert media channels is one of the most promising defenses against such threat models. They leverage WebRTC-based covert channels as a robust and practical approach against powerful traf- fic correlation analysis. At the same time, these solutions are difficult to combat through the traffic-blocking measures commonly used by censorship authorities. In this dissertation, we propose TorKameleon, a censorship evasion solution de- signed to protect Tor users with increased censorship resistance against powerful traffic correlation attacks executed by global adversaries. The system is based on flexible K- anonymization input circuits that can support TLS tunneling and WebRTC-based covert channels before forwarding users’ original input traffic to the Tor network. Our goal is to protect users from machine and deep learning correlation attacks between incom- ing user traffic and observed traffic at different Tor network relays, such as middle and egress relays. TorKameleon is the first system to implement a Tor pluggable transport based on parameterizable TLS tunneling and WebRTC-based covert channels. We have implemented the TorKameleon prototype and performed extensive validations to ob- serve the correctness and experimental performance of the proposed solution in the Tor environment. With these evaluations, we analyze the necessary tradeoffs between the performance of the standard Tor network and the achieved effectiveness and performance of TorKameleon, capable of preserving the required unobservability properties.Redes de anonimização como o Tor e soluções ou ferramentas semelhantes são meios poderosos de aumentar a anonimidade e a privacidade das comunicações de utilizadores da Internet . O Tor é atualmente a rede de anonimato mais utilizada por delatores para divulgar informações confidenciais e denunciar medidas de censura tais como violações de direitos civis e da liberdade de expressão, ou falhas nas garantias de livre acesso à informação. No entanto, estudos recentes mostram que o Tor é vulnerável a adversários globais ou a entidades que colaboram entre si para garantir a censura online. Neste cenário competitivo e de jogo do “gato e do rato”, é possível verificar que à medida que novas soluções de censura e vigilância são investigadas, novos sistemas melhorados para a preservação de anonimato são também apresentados e refinados. O encapsulamento de pacotes IP em túneis encapsulados em protocolos de media são uma das mais promissoras soluções contra os novos modelos de ataque à anonimidade. Estas soluções alavancam canais encobertos em protocolos de media baseados em WebRTC para resistir a poderosos ataques de correlação de tráfego e a medidas de bloqueios normalmente usadas pelos censores. Nesta dissertação propomos o TorKameleon, uma solução desenhada para protoger os utilizadores da rede Tor contra os mais recentes ataques de correlação feitos por um modelo de adversário global. O sistema é baseado em estratégias de anonimização e reencaminhamento do tráfego do utilizador através de K nós, utilizando também encap- sulamento do tráfego em canais encobertos em túneis TLS ou WebRTC. O nosso objetivo é proteger os utilizadores da rede Tor de ataques de correlação implementados através de modelos de aprendizagem automática feitos entre o tráfego do utilizador que entra na rede Tor e esse mesmo tráfego noutro segmento da rede, como por exemplo nos nós de saída da rede. O TorKameleon é o primeiro sistema a implementar um Tor pluggable transport parametrizável, baseado em túneis TLS ou em canais encobertos em protocolos media. Implementamos um protótipo do sistema e realizamos uma extensa avalição expe- rimental, inserindo a solução no ambiente da rede Tor. Com base nestas avaliações, anali- zamos o tradeoff necessário entre a performance da rede Tor e a eficácia e a performance obtida do TorKameleon, que garante as propriedades de preservação de anonimato

    Operational moving target defences for improved power system cyber-physical security

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    In this work, we examine how Moving Target Defences (MTDs) can be enhanced to circumvent intelligent false data injection (FDI) attacks against power systems. Initially, we show how, by implementing state-of-the-art topology learning techniques, we can commit full-knowledge-equivalent FDI attacks against static power systems with no prior system knowledge. We go on to explore how naive applications of topology change, as MTDs, can be countered by unsupervised learning-based FDI attacks and how MTDs can be combined with physical watermarking to enhance system resilience. A novel intelligent attack, which incorporates dimensionality reduction and density-based spatial clustering, is developed and shown to be effective in maintaining stealth in the presence of traditional MTD strategies. In resisting this new type of attack, a novel implementation of MTD is suggested. The implementation uses physical watermarking to drive detection of traditional and intelligent FDI attacks while remaining hidden to the attackers. Following this, we outline a cyber-physical authentication strategy for use against FDI attacks. An event-triggered MTD protocol is proposed at the physical layer to complement cyber-side enhancements. This protocol applies a distributed anomaly detection scheme based on Holt-Winters seasonal forecasting in combination with MTD implemented via inductance perturbation. To conclude, we developed a cyber-physical risk assessment framework for FDI attacks. Our assessment criteria combines a weighted graph model of the networks cyber vulnerabilities with a centralised residual-based assessment of the physical system with respect to MTD. This combined approach provides a cyber-physical assessment of FDI attacks which incorporates both the likelihood of intrusion and the prospect of an attacker making stealthy change once intruded.Open Acces

    Applied Methuerstic computing

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    For decades, Applied Metaheuristic Computing (AMC) has been a prevailing optimization technique for tackling perplexing engineering and business problems, such as scheduling, routing, ordering, bin packing, assignment, facility layout planning, among others. This is partly because the classic exact methods are constrained with prior assumptions, and partly due to the heuristics being problem-dependent and lacking generalization. AMC, on the contrary, guides the course of low-level heuristics to search beyond the local optimality, which impairs the capability of traditional computation methods. This topic series has collected quality papers proposing cutting-edge methodology and innovative applications which drive the advances of AMC

    Applied Metaheuristic Computing

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    For decades, Applied Metaheuristic Computing (AMC) has been a prevailing optimization technique for tackling perplexing engineering and business problems, such as scheduling, routing, ordering, bin packing, assignment, facility layout planning, among others. This is partly because the classic exact methods are constrained with prior assumptions, and partly due to the heuristics being problem-dependent and lacking generalization. AMC, on the contrary, guides the course of low-level heuristics to search beyond the local optimality, which impairs the capability of traditional computation methods. This topic series has collected quality papers proposing cutting-edge methodology and innovative applications which drive the advances of AMC

    Development of variable voltage variable frequency drive system for induction motor speed control

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    This project describes the development of a Variable Voltage Variable Frequency (VVVF) system that controls the speed of Induction Motor (IM) at specific speed. Texas Instrument C2000 Microcontroller (TMS320F28335) has been used in this project as the interface between the control design with the IM. The Texas Instrument microcontroller has been combined with the MATLAB/Simulink and the VVVF system as the communication interface for processing the speed control system. The combination between power electronic circuits and microcontroller along with variable voltage variable frequency (VVVF) technique is able to control the target speed of IM. The target value of VVVF is implemented inside Lookup table and has been combined with the Proportional Integral (PI) speed control that generates the signal into the sinusoidal pulse width modulation (SPWM) for inverter operation. The SPWM signal is produced from the microcontroller with the instruction from MATLAB/Simulink, where the controller performs the output of the motor speed. The PI speed control receives the output of a closed loop feedback system from the motor speed and the error signal is reduced to achieve the value of desired speed reference. In the conclusion, the VVVF closed loop system is very useful to control the desired speed of motor at different variable voltage and variable frequency value. As collected for the results, its show, the VVVF with PI speed control can achieve the actual speed for the IM at 1297rpm and 1499rpm when the reference speeds have been set at 1300rpm and 1500rpm respectively. At the end it can be concluded that the VVVF combined with microcontroller have created an ecosystem for speed control that have achieved the objectives

    Entropy in Image Analysis II

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    Image analysis is a fundamental task for any application where extracting information from images is required. The analysis requires highly sophisticated numerical and analytical methods, particularly for those applications in medicine, security, and other fields where the results of the processing consist of data of vital importance. This fact is evident from all the articles composing the Special Issue "Entropy in Image Analysis II", in which the authors used widely tested methods to verify their results. In the process of reading the present volume, the reader will appreciate the richness of their methods and applications, in particular for medical imaging and image security, and a remarkable cross-fertilization among the proposed research areas

    SLEPX: An Efficient Lightweight Cipher for Visual Protection of Scalable HEVC Extension

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    This paper proposes a lightweight cipher scheme aimed at the scalable extension of the High Efficiency Video Coding (HEVC) codec, referred to as the Scalable HEVC (SHVC) standard. This stream cipher, Symmetric Cipher for Lightweight Encryption based on Permutation and EXlusive OR (SLEPX), applies Selective Encryption (SE) over suitable coding syntax elements in the SHVC layers. This is achieved minimal computational complexity and delay. The algorithm also conserves most SHVC functionalities, i.e. preservation of bit-length, decoder format-compliance, and error resilience. For comparative analysis, results were taken and compared with other state-of-art ciphers i.e. Exclusive-OR (XOR) and the Advanced Encryption Standard (AES). The performance of SLEPX is also compared with existing video SE solutions to confirm the efficiency of the adopted scheme. The experimental results demonstrate that SLEPX is as secure as AES in terms of visual protection, while computationally efficient comparable with a basic XOR cipher. Visual quality assessment, security analysis and extensive cryptanalysis (based on numerical values of selected binstrings) also showed the effectiveness of SLEPX’s visual protection scheme for SHVC compared to previously-employed cryptographic technique

    International Conference on Civil Infrastructure and Construction (CIC 2020)

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    This is the proceedings of the CIC 2020 Conference, which was held under the patronage of His Excellency Sheikh Khalid bin Khalifa bin Abdulaziz Al Thani in Doha, Qatar from 2 to 5 February 2020. The goal of the conference was to provide a platform to discuss next-generation infrastructure and its construction among key players such as researchers, industry professionals and leaders, local government agencies, clients, construction contractors and policymakers. The conference gathered industry and academia to disseminate their research and field experiences in multiple areas of civil engineering. It was also a unique opportunity for companies and organizations to show the most recent advances in the field of civil infrastructure and construction. The conference covered a wide range of timely topics that address the needs of the construction industry all over the world and particularly in Qatar. All papers were peer reviewed by experts in their field and edited for publication. The conference accepted a total number of 127 papers submitted by authors from five different continents under the following four themes: Theme 1: Construction Management and Process Theme 2: Materials and Transportation Engineering Theme 3: Geotechnical, Environmental, and Geo-environmental Engineering Theme 4: Sustainability, Renovation, and Monitoring of Civil InfrastructureThe list of the Sponsors are listed at page 1

    Beyond The Words: Paratextual And Bibliographic Traces Of The Other Reader In British Literature, 1760-1897

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    Over the course of the late eighteenth and early nineteenth centuries, compounding technological improvements and expanding education result in unprecedented growth of the reading audience in Britain. This expansion creates a new relationship with the author, opening the horizon of the authorial imagination beyond the discourse community from which the author and the text originate. The relational gap between the author and this new audience manifests as the Other Reader, an anxiety formation that the author reacts to and attempts to preempt. This dissertation tracks these reactions via several authorial strategies that address the alienation of the Other Reader, including the use of prefaces, footnotes, margin notes, asterisks, and poioumena. The deployment of such paratextual and bibliographic tools allow the author to manage the fear of the Other Reader while still addressing their text primarily to their own discourse community
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