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Aringunram, Ravichandran. "Secure communication services for distributed conference system." [Gainesville, Fla.]: University of Florida, 2002. http://purl.fcla.edu/fcla/etd/UFE0000505.
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Szabo, Florian Akos. "Modelling of secure communication system for IoT enabled waste management system." Thesis, Luleå tekniska universitet, Datavetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76028.
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Urban expansion is a key driving force of our modern world. Increasing environmental footprint is an example issue that is directly caused by it. The city of St. Petersburg employs on average almost 500 garbage trucks on a daily basis and spends more than 1 million US Dollars every year to collect, process and manage waste. In order for megacities, such as St. Petersburg, to cope with its effects, new ideas are needed. This seems to be an obvious area in which technology can be used to improve current practices and help save resources. In this study, we investigate how the Internet of Things, blockchain and Quantum Key Distribution systems can be integrated to provide a safe and efficient method for improving the waste management process in the context of Smart City projects. Our implemented simulations in Mininet show that there are some clear challenges with regards to the adoption of blockchain technology in an IoT environment. However, the integration of quantum channels and the use of Quantum Key Distribution within the blockchain infrastructure shows good potential for balancing the advantages and disadvantages of blockchain. With the implemented simulations we demonstrate the superior capabilities of the Proof of Infrastructure blockchain solution, which can facilitate secure transactions within the waste management scenario.
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Zakria, Saber Nabil Shohdy. "Secure DS-CDMA communication system using chaotic and FPGA." Thesis, University of Kent, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274350.
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Tulasidas, Sivanesan. "Secure expandable communication framework for POCT system development and deployment." Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/17132.
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Health-care delivery in developing countries has many challenges because they do not have enough resources for meeting the healthcare needs and they lack testing lab infras- tructures in communities. It has been proven that Point-Of-Care (POC) testing can be considered as one of the ways to resolve the crisis in healthcare delivery in these com- munities. The POC testing is a mission critical processes in which the patient conduct tests outside of laboratory environment and it needs a secure communication system of architecture support which the research refers as POCT system Almost every ten years there will be a new radio access technology (RAT) is released in the wireless communication system evolution which is primarily driven by the 3GPP standards organisation. It is challenging to develop a predictable communication sys- tem in an environment of frequent changes originated by the 3GPP and the wireless operators. The scalable and expandable network architecture is needed for cost-effective network management, deployment and operation of the POC devices. Security mecha- nisms are necessary to address the specific threats associated with POCT system. Se- curity mechanisms are necessary to address the specific threats associated with POCT system. The POCT system communication must provide secure storage and secure com- munication to maintain patient data privacy and security. The Federal Drug Admin- istration (FDA) reports the leading causes of defects and system failures in medical devices are caused by gaps between the requirements, implementation and testing. The research was conducted, and technical research contributions are made to resolve the issues and challenges related to the POCT system. A communication protocol implemented at the application level, independent of radio access technologies. A new methodology was created by combining Easy Approach to Requirement Specifications (EARS) methodology and Use Case Maps (UCM) model which is a new approach and it addresses the concerns raised by the FDA. Secure cloud architecture was created which is a new way of data storage and security algorithms models were designed to address the security threats in the POCT system. The security algorithms, secure cloud architecture and the communication protocol coexist together to provide Radio access technology Independent Secure and Expandable (RISE) POCT system. These are the contributions to new knowledge that came out of the research. The research was conducted with a team of experts who are the subject matter experts in the areas such as microfluidics, bio-medical, mechanical engineering and medicine.
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Singh, Shubhanker. "Efficient, Scalable and Secure Vehicular Communication System : An Experimental Study." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-286820.
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Awareness of vehicles’ surrounding conditions is important in today’s intelligent transportation system. A wide range of effort has been put in to deploy Vehicular Communication (VC) systems to make driving conditions safer and more efficient. Vehicles are aware of their surroundings with the help of authenticated safety beacons in VC systems. Since vehicles act according to the information conveyed by such beacons, verification of beacons plays an important role in becoming aware of and predicting the status of the sender vehicle. The idea of implementing secure mechanisms to deal with a high rate of incoming beacons and processing them with high efficiency becomes a very important part of the whole VC network. The goal of this work was to implement a scheme that deals with a high rate of the incoming beacon, preserve non-repudiation of the accepted messages which contains information about the current and near-future status of the sender vehicle, and at the same time keep the computation overhead as low as possible. Along with this, maintaining user privacy from a legal point of view as well as from a technical perspective by implementing privacy-enhancing technologies. These objectives were achieved by the introduction of Timed Efficient Stream Loss-Tolerant Authentication (TESLA), periodic signature verification, and cooperative verification respectively. Four different scenarios were implemented and evaluated, starting and building upon the baseline approach. Each approach addressed the problems that were aimed at this work and results show improved scalability and efficiency with the introduction of TESLA, periodic signature verification, and cooperative verification.<br>Medvetenheten om fordons omgivande förhållanden är viktig i dagens intelligenta transportsystem. Ett stort antal ansträngningar har lagts ned för att distribuera VC system för att göra körförhållandena säkrare och effektivare. Fordon är medvetna om sin omgivning med hjälp av autentiserade säkerhetsfyrar i VC system. Eftersom fordon agerar enligt den information som förmedlas av sådana fyrar, spelar verifiering av fyrar en viktig roll för att bli medveten om och förutsäga avsändarfordonets status. Idén att implementera säkra mekanismer för att hantera en hög frekvens av inkommande fyrar och bearbeta dem med hög effektivitet blir en mycket viktig del av hela VC nätverket. Målet med detta arbete var att implementera ett schema som behandlar en hög hastighet för det inkommande fyren, bevara icke-förkastelse av de accepterade meddelandena som innehåller information om den aktuella och närmaste framtida statusen för avsändarfordonet och samtidigt håll beräkningen så låg som möjligt. Tillsammans med detta upprätthåller användarnas integritet ur juridisk synvinkel såväl som ur ett tekniskt perspektiv genom att implementera integritetsförbättrande teknik. Dessa mål uppnåddes genom införandet av TESLA, periodisk signatur verifiering respektive samarbets verifiering. Fyra olika scenarier implementerades och utvärderades med utgångspunkt från baslinjemetoden. Varje tillvägagångssätt tog upp de problem som riktades mot detta arbete och resultaten visar förbättrad skalbarhet och effektivitet med införandet av TESLA, periodisk signatur verifiering och samarbets verifiering.
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Hu, Nan. "SECURE IMAGE PROCESSING." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_theses/448.
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In todays heterogeneous network environment, there is a growing demand for distrusted parties to jointly execute distributed algorithms on private data whose secrecy needed to be safeguarded. Platforms that support such computation on image processing purposes are called secure image processing protocols. In this thesis, we propose a new security model, called quasi information theoretic (QIT) security. Under the proposed model efficient protocols on two basic image processing algorithms linear filtering and thresholding are developed. For both problems we consider two situations: 1) only two parties are involved where one holds the data and the other possesses the processing algorithm; 2) an additional non-colluding third party exists. Experiments show that our proposed protocols improved the computational time significantly compared with the classical cryptographical couterparts as well as providing reasonable amount of security as proved in the thesis
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Wu, Hao, Zhiping Zheng, and Naitong Zhang. "A NEW TYPE OF SOFTWARE ORIENTED SECURE SYSTEM FOR WIRELESS COMMUNICATION." International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/608292.
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International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada<br>Wireless information transmission is easy to be suffered from various threats in an open environment. In this paper, we proposed a new type of software oriented secure system for direct wireless information transmission. We first present the special functions and requirements, which have to be satisfied during introducing the secure system. Then, we divide the secure system into three stages: normal operating stage, key presetting stage, and key replanting stage. The security, reliability and the computing complexity of this system are analyzed in this paper. Finally, we carried out this secure system by software and proved the availability.
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Wang, Yan. "A Secure Gateway Localization and Communication System for Vehicular Ad Hoc Networks." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24034.
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Intelligent Transport System (ITS) has become a hot research topic over the past decades. ITS is a system that applies the following technologies to the whole transportation management system efficiently, including information technique, wireless communication, sensor networks, control technique, and computer engineering. ITS provides an accurate, real time and synthetically efficient transportation management system. Obviously, Vehicular Ad Hoc NETworks (VANETs) attract growing attention from both the research community and industry all over the world. This is because a large amount of applications are enabled by VANETs, such as safety related applications, traffic management, commercial applications and general applications. When connecting to the internet or communicating with different networks in order to access a variety of services using VANETs, drivers and passengers in different cars need to be able to exchange messages with gateways from their vehicles. A secure gateway discovery process is therefore critical, because vehicles should not be subject to security attacks while they are communicating; however, currently there is no existing protocol focusing on secure gateway discovery.
In this thesis, we first analyze and compare current existing secure service discovery protocols and then we propose a Secure Gateway Localization and Communication System for Vehicular Ad Hoc Networks (SEGAL), which concentrates on the security issue in gateway discovery. We focus on the authentication aspect by proposing secure cluster based VANETs, that can ensure the gateway discovery messages exchanged through secure clusters. We present the principle and specific process of our SEGAL protocol and analyze its performance to guarantee its outstanding practical applicability.
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Goméz, Villanueva Daniel. "Secure E-mail System for Cloud Portals : Master Thesis in Information and Communication Systems Security." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-108080.
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Email is a well established technology used worldwide for enterprise and private communication through the Internet. It allows people to communicate using text, but also other information formats used either as HTML or attached files. The communication is performed without the need of synchronized endpoints, based on the use of email servers that take care of storing and forwarding email letters. All these properties and much more standardized ones do not include security, which makes the choice of service provider hard when the letters sent in the email system include sensitive information. In the last few years there has been a big interest and growth in the area of cloud computing. Placing resources (computers, applications, information) out of local environments, thanks to the high speed connections in the Internet, provides countless possibilities. Actually, even email systems can be deployed in cloud computing environments, including all the email services (interface, client, and server) or a part of them. From a security point of view, the use of cloud computing leads to many threats generated by external parties and even the cloud providers. Because of these reasons, this work intends to present an innovative approach to security in a cloud environment, focusing on the security of an email system. The purpose is to find a solution for an email system deployable in a cloud environment, with all the functionality deployed on a external machine. This email system must be completely protected, minimizing the actions taken by the user, which should just connect to a portal through a web browser. Along this report there are details about the foundations, progress and findings of the research that has been carried out. The main objectives involve: researching on the concepts and state of the art of cloud computing, email systems and security; presenting a cloud computing architecture that will take care of the general aspects of security; designing an email system for that architecture that contains mechanisms protecting it from the possible security threats; and finally, implementing a simplified version of the design to test and prove the feasibility of it. After all the mentioned activities, the findings are commented, mentioning the applicability of research results to the current situation. Obviously, there is place for more research in depth of several topics related to cloud computing and email, that is why some of them are suggested.
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MENG, LI. "A BUILDING BLOCK APPROACH FOR DESIGNING SELF-SYNCHRONOUS CHAOTIC SYSTEMS FOR SECURE COMMUNICATION." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1057759148.
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Alzahrani, Naif Saeed. "A Secure Anti-Counterfeiting System using Near Field Communication, Public Key Cryptography, Blockchain, and Bayesian Games." PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/5038.
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Counterfeit products, especially in the pharmaceutical sector, have plagued the international community for decades. To combat this problem, many anti-counterfeiting approaches have been proposed. They use either Radio Frequency Identification (RFID) or Near Field Communication (NFC) physical tags affixed to the products. Current anti-counterfeiting approaches detect two counterfeiting attacks: (1) modifications to a product's tag details, such as changing the expiration date; and (2) cloning of a genuine product's details to reuse on counterfeit products. In addition, these anti-counterfeiting approaches track-and-trace the physical locations of products as the products flow through supply chains.
Existing approaches suffer from two main drawbacks. They cannot detect tag reapplication attacks, wherein a counterfeiter removes a legitimate tag from a genuine product and reapplies it to a counterfeit or expired product. Second, most existing approaches typically rely on a central server to authenticate products. This is not scalable and creates tremendous processing burden on the server, since significant volumes of products flood through the supply chain's nodes. In addition, centralized supply chains require substantial data storage to store authentication records for all products. Moreover, as with centralized systems, traditional supply chains inherently have the problem of a single-point of failure.
The thesis of this dissertation is that a robust, scalable, counterfeiting-resistant supply chain that addresses the above drawbacks and can be simultaneously achieved by (i) using a combination of NFC tags on products and a distributed ledger such as blockchain for reapplication-proof, decentralized, and transparent product authentication (ii) a novel game-theoretical consensus protocol for enforcing true decentralization, and enhancing the protocol's security and performance.
In this dissertation, we first propose a new Tag Reapplication Detection (TRD) system to detect reapplication attacks using low-cost NFC tags and public key cryptography. To detect reapplication attacks, TRD tracks the number of times a tag has been read in the supply chain using a 'central' authentication server. Second, leveraging the blockchain technology, we propose the Block-Supply Chain, a transformation of TRD into a decentralized supply chain. In this chain, each node maintains a blockchain (distributed public ledger) per product. This blockchain comprises chained blocks, where each is an authentication event. The Block-Supply Chain can detect tag reapplication attacks and can replace the centralized supply chain design, thus overcoming the centralization issues.
One of the fundamental characteristics of blockchain technology is the consensus protocol. Consensus protocols ensure that all nodes in the blockchain network agree on the validity of a block to be included in the public ledger. The first and most popular of the existing consensus protocols is Proof of Work (PoW). However, PoW requires massive computational effort, resulting in high energy and computing resources consumption. Alternatively, Byzantine Fault Tolerance (BFT) protocols, such as Tendermint, were adapted in blockchain technology to be efficient and easy to implement. Nevertheless, not all of BFT protocols guarantee true decentralization, and they are mostly based on fixed-validators. BFT fixed-validators protocols typically rely on fixed, static validators responsible for validating all newly proposed blocks. This opens the door for adversaries to launch several attacks on these validators, such as Distributed Denial of Service (DDoS) and Eclipse attacks. In contrast, a truly decentralized protocol ensures that variable sets of anonymous validators execute the blocks' validations. Building on this observation, we propose the TrueBFT, a truly decentralized BFT-based consensus protocol that does not require PoW and randomly employs a different set of validators on each block's proposal. TrueBFT is designed for permissioned blockchains (in such blockchains, the participants who can transact on the blockchain are limited, and each participant is required to have permission to join the system). Our simulations show that TrueBFT offers remarkable performance with a satisfactory level of security compared to the state-of-the-art protocol Tendermint.
Another issue with current consensus protocols, particularly the BFT, is that the majority of them do not take the number of employed validators into consideration. The number of validators in a blockchain network influences its security and performance substantially. In response, we integrate a game theoretical model into TrueBFT that analyzes the risk likelihood of each proposer (i.e., the node that creates and proposes the new block). Consequently, each time a new block is proposed, the 'number of validators' becomes proportional to the risk likelihood block's proposer. Additionally, the game model reinforces the honest behavior of the validators by rewarding honest validators and punishing dishonest ones.
Together, TRD, Block-Supply Chain, and the game-theoretical TrueBFT consensus protocol enable robust, scalable, decentralized anti-counterfeiting supply chain that is resistant to tag reapplication attacks, as well as attacks to consensus protocols such as DDoS and Eclipse attacks.
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De, Bruyn Daniel Nicholas. "Investigation and development of a system for secure synchronisation in a wireless mesh network." Thesis, [Bloemfontein?] : Central University of Technology, Free State, 2010. http://hdl.handle.net/11462/132.
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Thesis (M. Tech.(Electrical Engineering)) -- Central University of technology, Free State, 2010<br>This dissertation gives an overview of the research done in developing a protocol to synchronise information in a secure wireless mesh network. Alternative methods to control wireless devices were investigated in the non-controlled frequency spectrum.
The aim of the research was to develop a protocol that can be loaded on a micro-controller with limited intelligence, controlling endpoints. The protocol minimises human interference and automatically negotiates which device becomes the master controller. The device is able to discover and locate neighbour devices in range. The device has the capability to be stationary or mobile and host multiple control endpoints.
Control endpoints can be digital or analogue, input or output, and belongs to a group like security, lighting or irrigation. These capabilities can change according to the solution’s requirements. Control endpoints with the same capabilities must be able to establish a connection between each other. An endpoint has a user-friendly name and can update the remote endpoint with the description. When a connection is established both endpoints update each other with their user-friendly name and their status. A local endpoint can trigger a certain action on a receiving control point.
The system was tested with a building monitoring system because it is static and a less expensive choice, thus making the evaluation more suitable. A simulator for a personal computer was developed to evaluate the new protocol. Finally, the protocol was implemented and tested on a micro-controller platform.
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Ng, Wing Kwan. "Energy efficient and secure wireless communication systems." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/42810.
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Orthogonal frequency division multiple access (OFDMA),
multiple--input multiple--output (MIMO), and base station (BS)
cooperation are the core techniques for the next generation wireless
communication systems. As the communication systems evolve, both
service providers and users are demanding not only high data rates,
but also energy efficiency and data security. As a result, it is
necessary to design novel resource allocation algorithms that meet
these new needs. This dissertation develops four resource allocation
algorithms which are tailored for different design goals and
communication environments.
For systems employing the combination of OFDMA and
decode-and-forward (DF) relaying technologies, we propose a novel
resource allocation algorithm for secure communication. The proposed
algorithm takes into account artificial noise generation to combat a
passive multiple antenna eavesdropper and the effects of imperfect
channel state information at the transmitter (CSIT).
Subsequently, we investigate the energy efficiency of OFDMA systems
which also provide communication security. We formulate the resource
allocation algorithm design as a non-convex optimization problem.
By exploiting the properties of fractional programming, the
considered non-convex optimization problem is transformed to an
equivalent convex optimization problem with a tractable solution,
which can be obtained with an iterative algorithm.
Thirdly, we study resource allocation for energy efficient
communication in OFDMA downlink networks with a large number of
transmit antennas. Our proposed resource allocation algorithm takes
into account the circuit power consumption, imperfect CSIT, a
minimum data rate requirement, and a maximum tolerable channel
outage probability.
Lastly, we propose a resource allocation algorithm for energy efficient communication in OFDMA downlink networks with cooperative
BSs. The resource allocation algorithm design problem is formulated
as a non-convex optimization problem which takes into account the
circuit power consumption, the limited backhaul capacity, and the
minimum required data rate for joint BS zero-forcing beamforming
(ZFBF) transmission. By using the concept of perturbation function,
we show that the duality gap in the considered system is always zero
under some general conditions, despite the non-convexity of the
primal problem. Thus, an efficient closed-form power allocation
solution for maximization of the energy efficiency of data
transmission is derived.
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Dawson, Robert Edward. "Secure communications for critical infrastructure control systems." Thesis, Queensland University of Technology, 2008. https://eprints.qut.edu.au/20710/1/Robert_Dawson_Thesis.pdf.
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In March 2000, 1 million litres of raw sewage was released into the water system of Maroochy Shire on Queensland’s sunshine coast. This environmental disaster was caused by a disgruntled ex-contractor using a radio transmitter to illicitly access the electronically controlled pumps in the control system. In 2007 CNN screened video footage of an experimental attack against a electrical generator. The attack caused the generator to shake and smoke, visually showing the damage caused by cyber attack. These attacks highlight the importance of securing the control systems which our critical infrastructures depend on. This thesis addresses securing control systems, focusing on securing the communications for supervisory control and data acquisition (SCADA) systems. We review the architectures of SCADA systems and produce a list of the system constraints that relate to securing these systems. With these constraints in mind, we survey both the existing work in information and SCADA security, observing the need to investigate further the problem of secure communications for SCADA systems. We then present risk modelling techniques, and model the risk in a simple SCADA system, using the ISM, a software tool for modelling information security risk. In modelling the risk, we verify the hypothesis that securing the communications channel is an essential part of an effective security strategy for SCADA systems. After looking at risk modelling, and establishing the value of securing communications, we move on to key management for SCADA systems. Appropriate key management techniques are a crucial part of secure communications, and form an important part of the contributions made in this work. We present a key management protocol that has been designed to run under the constraints specific to SCADA systems. A reductionist security proof is developed for a simplified version of the protocol, showing it is secure in the Bellare Rogaway model.
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Dawson, Robert Edward. "Secure communications for critical infrastructure control systems." Queensland University of Technology, 2008. http://eprints.qut.edu.au/20710/.
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In March 2000, 1 million litres of raw sewage was released into the water system of Maroochy Shire on Queensland’s sunshine coast. This environmental disaster was caused by a disgruntled ex-contractor using a radio transmitter to illicitly access the electronically controlled pumps in the control system. In 2007 CNN screened video footage of an experimental attack against a electrical generator. The attack caused the generator to shake and smoke, visually showing the damage caused by cyber attack. These attacks highlight the importance of securing the control systems which our critical infrastructures depend on. This thesis addresses securing control systems, focusing on securing the communications for supervisory control and data acquisition (SCADA) systems. We review the architectures of SCADA systems and produce a list of the system constraints that relate to securing these systems. With these constraints in mind, we survey both the existing work in information and SCADA security, observing the need to investigate further the problem of secure communications for SCADA systems. We then present risk modelling techniques, and model the risk in a simple SCADA system, using the ISM, a software tool for modelling information security risk. In modelling the risk, we verify the hypothesis that securing the communications channel is an essential part of an effective security strategy for SCADA systems. After looking at risk modelling, and establishing the value of securing communications, we move on to key management for SCADA systems. Appropriate key management techniques are a crucial part of secure communications, and form an important part of the contributions made in this work. We present a key management protocol that has been designed to run under the constraints specific to SCADA systems. A reductionist security proof is developed for a simplified version of the protocol, showing it is secure in the Bellare Rogaway model.
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Antolino, Rivas David. "Reputation systems and secure communication in vehicular networks." Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/117532.
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A thorough review of the state of the art will reveal that most VANET applications rely on Public Key Infrastructure (PKI), which uses user certificates managed by a Certification Authority (CA) to handle security. By doing so, they constrain the ad-hoc nature of the VANET imposing a frequent connection to the CA to retrieve the Certificate Revocation List (CRL) and requiring some degree of roadside infrastructure to achieve that connection. Other solutions propose the usage of group signatures where users organize in groups and elect a group manager. The group manager will need to ensure that group members do not misbehave, i.e., do not spread false information, and if they do punish them, evict them from the group and report them to the
CA; thus suffering from the same CRL retrieval problem.
In this thesis we present a fourfold contribution to improve security in VANETs. First and foremost, Chains of Trust describes a reputation system where users disseminate Points of Interest (POIs) information over the network while their privacy remains protected. It uses asymmetric cryptography and users are responsible for the generation of their own pair of public and
private keys. There is no central entity which stores the information users input into the system; instead, that information is kept distributed among the vehicles that make up the network. On top of that, this system requires no roadside infrastructure. Precisely, our main objective with Chains of Trust was to show that just by relying on people¿s driving habits and the sporadic nature of their encounters with other drivers a successful reputation system could be built.
The second contribution of this thesis is the application simulator poiSim. Many¿s the time a new VANET application is presented and its authors back their findings using simulation results from renowned networks simulators like ns-2. The major issue with network simulators is that they were not designed with that purpose in mind and handling simulations with hundreds of nodes requires a massive processing power. As a result, authors run small simulations (between 50 and 100 nodes) with vehicles that move randomly in a squared area instead of using real maps, which rend unrealistic results. We show that by building tailored application simulators we can obtain more realistic results. The application simulator poiSim processes a realistic mobility trace produced by a Multi-agent Microscopic Traffic Simulator developed at ETH Zurich, which accurately describes the mobility patterns of 259,977 vehicles over regional maps of Switzerland for 24 hours. This simulation runs on a desktop PC and lasts approximately 120 minutes.
In our third contribution we took Chains of Trust one step further in the protection of user privacy to develop Anonymous Chains of Trust. In this system users can temporarily exchange their identity with other users they trust, thus making it impossible for an attacker to know in all certainty who input a particular piece of information into the system. To the best of our knowledge, this is the first time this technique has been used in a reputation system.
Finally, in our last contribution we explore a different form of communication for VANETs. The vast majority of VANET applications rely on the IEEE 802.11p/Wireless Access in Vehicular Environments (WAVE) standard or some other form of radio communication. This poses a security risk if we consider how vulnerable radio transmission is to intentional jamming and
natural interferences: an attacker could easily block all radio communication in a certain area if his transmitter is powerful enough. Visual Light Communication (VLC), on the other hand, is resilient to jamming over a wide area because it relies on visible light to transmit information and ,unlike WAVE, it has no scalability problems. In this thesis we show that VLC is a secure and valuable form of communication in VANETs.
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Kharel, Rupak. "Design and implementation of secure chaotic communication systems." Thesis, Northumbria University, 2011. http://nrl.northumbria.ac.uk/4205/.
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Chaotic systems have properties such as ergodicity, sensitivity to initial conditions/parameter mismatches, mixing property, deterministic dynamics, structure complexity, to mention a few, that map nicely with cryptographic requirements such as confusion, diffusion, deterministic pseudorandomness, algorithm complexity. Furthermore, the possibility of chaotic synchronization, where the master system (transmitter) is driving the slave system (receiver) by its output signal, made it probable for the possible utilization of chaotic systems to implement security in the communication systems. Many methods like chaotic masking, chaotic modulation, inclusion, chaotic shift keying (CSK) had been proposed however, many attack methods later showed them to be insecure. Different modifications of these methods also exist in the literature to improve the security, but almost all suffer from the same drawback. Therefore, the implementation of chaotic systems in security still remains a challenge. In this work, different possibilities on how it might be possible to improve the security of the existing methods are explored. The main problem with the existing methods is that the message imprint could be found in the dynamics of the transmitted signal, therefore by some signal processing or pattern classification techniques, etc, allow the exposition of the hidden message. Therefore, the challenge is to remove any pattern or change in dynamics that the message might bring in the transmitted signal.
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Ursini, Leonora. "Optical Chaotic Transmission Systems For Secure Data Communication." Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3425929.
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The optical chaos dynamics are investigated for obtaining the secure transmission of an information message. A detailed
numerical analysis of an optical chaotic transmission system, based on the synchronization of two chaotic lasers is presented. At the transmitter, the chaotic waveform is superposed on the information message; at the receiver, the message is recovered by subtracting the synchronized chaotic wave from the received signal. The aim is the investigation of the system performance for various configurations. Original
methods are also proposed for improving the performance. Finally, an experimental set-up of the chaotic transmission system has been implemented.<br>L'attività di Ricerca, presentata in questa Tesi, è stata parte del Progetto di Rilevante Interesse Nazionale (PRIN), finanziato dal Ministero dell'Università e della Ricerca, e intitolato ``Trasmissione in fibra ottica su portante ottica caotica'' (PRIN200509125), svolto in collaborazione fra le Università di Padova, Pavia e l'Aquila.
La protezione nel trasferimento delle informazioni è, da sempre, una delle caratterisctiche più richieste ai mezzi di comunicazione. I metodi sia crittografici che steganografici,
atti a garantire sicurezza agli utenti che scambiano in rete dati sensibili, costituiscono un grosso filone di ricerca.
Lo scopo di questa Tesi è dimostrare la comunicazione di un messaggio su un canale in fibra ottica, utilizzando una tecnica che si basa sul principio di sincronizzazione di una coppia di laser, operanti nel regime caotico. Il caos deterministico è un regime di alcuni sistemi dinamici non-lineari, che si caratterizza con evoluzioni irregolari, fortemente dipendenti dalle condizioni iniziali. Il regime caotico, nei laser, si manifesta con rapide ed apparentemente casuali oscillazioni della forma d'onda emessa.
Nello schema di trasmissione, il trasmettitore è costituito da un generatore di messaggi e da un laser caotico, detto master, che funge da portante ottica; il messaggio d'informazione da trasmettere è opportunamente sovrapposto all'emissione del master, realizzando uno schema di protezione di tipo steganografico. Al ricevitore, l'estrazione del messaggio si basa sulla disponibilità di un altro laser, detto slave, che generi un'identica forma d'onda
caotica (sincronizzazione), da sottrarre al segnale trasmesso. Perchè ciò sia possibile, data la forte dipendenza del caos dalle condizioni iniziali e dai valori dei parametri dei laser, è necessario disporre di una coppia di laser avente parametri molto simili. Questo fatto, aggiunto ad una efficiente mascheratura del messaggio, rende molto difficile la decodifica da parte di un ascoltatore non autorizzato.
L'efficacia di tale tecnica si basa sulla qualità della sincronizzazione, che può degradarsi, oltre che per una scelta non corretta dei due laser, anche per gli effetti distorsivi della
fibra ottica su cui si trasmette il segnale, come attenuazione, dispersione cromatica, effetti nonlineari e di polarizzazione, e dal rumore.
In questa Tesi, si è studiato, da un punto di vista teorico e numerico il sistema caotico su fibra ottica, analizzandone le prestazioni per varie configurazioni. Lo studio ha riguardato: la generazione del caos di un laser a semiconduttore, mediante retroriflessione del segnale con uno specchio esterno; l'analisi della sincronizzazione con un laser gemello; la modellizzazione del canale ottico; l'analisi delle prestazioni del sistema caotico per la steganografia di messaggi digitali.
Nella Tesi, sono anche presentati metodi originali per migliorare le prestazioni di sicurezza e recupero del messaggio. Infine, è stato implementato anche un dimostratore del sistema, in collaborazione con l'Università di Pavia.
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Elkouny, Abdel-latif Ahmed Abdel-latif. "Real time secure communications using chaotic encryption systems." Thesis, University of Kent, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274326.
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Lei, Ao. "Dynamic key management for secure heterogeneous vehicular communication systems." Thesis, University of Surrey, 2018. http://epubs.surrey.ac.uk/845433/.
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Both research community and industry believe that Intelligent Transportation System (ITS) would be achievable in the next decade. ITS introduces information technology for the transportation vehicles and infrastructures and aims to improve road safety and traffic efficiency. Vehicular Communication Systems (VCS), provides a platform for the vehicles to exchange messages with network infrastructures (V2I) or other vehicles (V2V). Confidence in these messages can be achieved through secure group messaging. Furthermore, the reliability of ITS highly relies on the security level of VCS. Therefore, secure key management schemes are proposed to enhance network security, which involves two aspects, namely Group Key Management (GKM) and Key Handover which also known as key transfer. The first part manages keys among a communication group within small road area, whereas key handover transfers secret keys from one security domain to another. Three contributions related to secure key management are as follows. The first contribution focuses on managing group communication keys in an efficient way. The probability-based scheme describes a novel GKM scheme using leaving probabilities of vehicles to optimise the structure of key tree branches. The proposed scheme further decreases rekeying costs and releases network resources. The second contribution introduces the Distributed Ledger Technology (DLT) structure to simplify the key handover procedures between heterogeneous networks. The central managers are eliminated from the key handover participation list. The key handover data are encapsulated into transactions and the Blockchain is maintained by all the infrastructures distributively. Finally, the dynamic transaction collection period is replenished to further optimise the performance based on the framework in the second contribution. The collection period varies dynamically to flexibly fit the traffic level on the road. The scheme aims to raise key handover efficiency at peak hours, while reducing the computation burden at off-peak hours.
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Li, Hong Ping. "Secure proximity queries in mobile geo-social services." HKBU Institutional Repository, 2013. https://repository.hkbu.edu.hk/etd_ra/1551.
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Nilsson, Daniel. "Evaluation of Secure Long Distance Communication in Non-Urban Environments." Thesis, Luleå tekniska universitet, Rymdteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-67808.
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Shehata, Ahmed Alaael-Din Rohiem. "Secure computer communications and databases using chaotic encryption systems." Thesis, University of Kent, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324713.
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Aghakhanian, Fereydani Behrooz. "Secure Vehicular Communication Systems: Cross-Domain VPKI, Design and Implementation." Thesis, KTH, Kommunikationsnät, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-137112.
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Enabling communication among vehicles on the road has advantages, but it also introduces a number of security drawbacks. A Vehicular PKI (VPKI) provides an infrastructure that brings security and privacy within the VPKI domain. But when it comes to establishing a trust model among multiple VPKI domains, a new trust model is needed in order to facilitate travelling across domains. This project proposes an approach and partially implements a scalable and efficient Cross-Domain VPKI trust model that, first, enables VPKI domains to establish different levels of trust with each other and, second, it suggests that a Domain CA (DCA) in each domain to evaluate trustworthiness of vehicle’s Long Term Certificate (LTC). As result, CAs in VPKI domains will have more granular control over issuing pseudonym Foreign Certificates for a vehicle that travels into their domain.
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Uluagac, Arif Selcuk. "A secure communication framework for wireless sensor networks." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34713.
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Today, wireless sensor networks (WSNs) are no longer a nascent technology and future networks, especially Cyber-Physical Systems (CPS) will integrate more sensor-based systems into a variety of application scenarios. Typical application areas include medical, environmental, military, and commercial enterprises. Providing security to this diverse set of sensor-based applications is necessary for the healthy operations of the overall system because untrusted entities may target the proper functioning of applications and disturb the critical decision-making processes by injecting false information into the network. One way to address this issue is to employ en-route-filtering-based solutions utilizing keys generated by either static or dynamic key management schemes in the WSN literature. However, current schemes are complicated for resource-constrained sensors as they utilize many keys and more importantly as they transmit many keying messages in the network, which increases the energy consumption of WSNs that are already severely limited in the technical capabilities and resources (i.e., power, computational capacities, and memory) available to them.
Nonetheless, further improvements without too much overhead are still possible by sharing a dynamically created cryptic credential. Building upon this idea, the purpose of this thesis is to introduce an efficient and secure communication framework for WSNs. Specifically, three protocols are suggested as contributions using virtual energies and local times onboard the sensors as dynamic cryptic credentials: (1) Virtual Energy-Based Encryption and Keying (VEBEK); (2) TIme-Based DynamiC Keying and En-Route Filtering (TICK); (3) Secure Source-Based Loose Time Synchronization (SOBAS) for WSNs.
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Hewage, Kasun. "Towards a secure synchronous communication architecture for low-power wireless networks." Licentiate thesis, Uppsala universitet, Avdelningen för datorteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-284331.
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The Internet of Things (IoT) is becoming the future Internet where most day-to-day devices are connected to the Internet. These devices are often resource constrained and use low-power wireless communication. Hence networks of them are called low-power and lossy networks (LLNs). LLN devices may be used in critical applications such as health care, traffic and industrial plants that concern privacy and security, thus their communication has to be protected from malicious activities. LLNs face threats at different levels ranging from transmitting bits wirelessly to applications. In this thesis, we primarily explore LLN security issues related to application protocols and attacks that target the availability of LLNs. Particularly, we investigate compressing messages of a transport security protocol, DTLS, to make it efficient for LLNs. The IETF proposes to use DTLS for securing CoAP, a specialized web protocol for constrained devices. Furthermore, we experimentally study disrupting the communication of one of the state of the art LLN protocols, Glossy, by attacking its core mechanism. Secondarily, we aim at improving the performance of TCP in LLNs with mobility over a reliable data link protocol. To this end, we use a Glossy-based communication protocol, LWB, as a reliable data link protocol. We plan to use the evaluation of this work as a stepping stone towards comparing the performance of secure Glossy-based communication protocols. The main contributions of this thesis are threefold. We propose novel message compression mechanisms for DTLS messages. We also present novel attacks on Glossy, evaluate the effectiveness of them experimentally, and propose potential counter measures. Finally, we show that a reliable data link protocol can improve the performance of TCP in static and mobile settings.
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Chen, Hejun. "A framework for secure mobility in wireless overlay networks." Thesis, Nelson Mandela Metropolitan University, 2006. http://hdl.handle.net/10948/819.
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Various wireless networks are widely deployed world wide. Current technologies employed in these networks vary widely in terms of bandwidths, latencies, frequencies, and media access methods. Most existing wireless network technologies can be divided into two categories: those that provide a low-bandwidth service over a wide geographic area, for example UMTS, and those that provide a high bandwidth service over a narrow geographic area, for example 802.11. Although it would be desirable to provide a high- bandwidth service over a wide coverage region to mobile users all the time, no single wireless network technology simultaneously satisfies these require- ments. Wireless Overlay Networks, a hierarchical structure of wireless personal area, local area, and wide area data networks, is considered as an efficient and scalable way to solve this problem. Due to the wide deployment of UMTS and 802.11 WLAN, this study attempts to combine them to implement the concept of Wireless Overlay Net- works. Furthermore, the information transmitted over this Wireless Overlay Networks is protected in terms of authentication, integrity and confidentiality. To achieve this goal, this study aims to combine GPRS, Mobile IP and IPSec to propose a framework for secure mobility in Wireless Overlay Networks. The framework is developed in three steps: Firstly, this study addresses the problem of combining GPRS and Mo- bile IP, so that GPRS users are provided with Mobile IP service. This results in presenting a uniform Mobile IP interface to peers regardless of whether mobile users use UMTS or 802.11 WLAN. Secondly, this study discovers the existing problem when combining Mobile IP and IPSec, and proposes a Dual Home Agent Architecture to achieve secure mobility. Finally, based on the output of the previous two steps, a complete framework is proposed, which achieves secure mobility in Wireless Overlay Networks, specifically, in UMTS and 802.11 WLAN. The framework also implements seamless handover when mobile users switch between UMTS and 802.11. This results in UMTS and 802.11 WLAN looking like a single network when participating in this framework, and presents seamless and secure mobility.
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Lee, Chungyong. "Noise reduction methods for chaotic signals with application to secure communications." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/14823.
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Cui, Zheng. "Design and implementation of secure communications for a distributed mobile computing system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0016/MQ57103.pdf.
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Rostrom, Timothy James. "Framework to Secure Cloud-based Medical Image Storage and Management System Communications." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/3124.
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Picture Archiving and Communication Systems (PACS) have been traditionally constrained to the premises of the healthcare provider. This has limited the availability of these systems in many parts of the world and mandated major costs in infrastructure for those who employ them. Public cloud services could be a solution that eases the cost of ownership and provides greater flexibility for PACS implementations. This could make it possible to bring medical imaging services to places where it was previously unavailable and reduce the costs associated with these services for those who utilize them. Moving these systems to public cloud infrastructure requires that an authentication and encryption policy for communications is established within the PACS environment to mitigate the risks incurred by using the Internet for the communication of medical data. This thesis proposes a framework which can be used to create an authenticated and encrypted channel to secure the communications with a cloud-based PACS. This framework uses the Transport Layer Security (TLS) protocol and X.509 certificates to create a secured channel. An enterprise style PKI is used to provide a trust model to authorize endpoints to access the system. The validity of this framework was tested by creating a prototype cloud-based PACS with secured communications. Using this framework will provide a system based on trusted industry standards which will protect the confidentiality and integrity of medical data in transit when using a cloud-based PACS service.
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Khodaei, Mohammad. "Secure Vehicular Communication Systems: Design and Implementation of a Vehicular PKI (VPKI)." Thesis, KTH, Kommunikationsnät, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-119820.
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The idea of vehicular communication systems could bring more safety, immunity and assurance in driving while it poses a variety of applications in traffic efficiency, driver assistance, environmental hazards, road conditions and infotainment. The aim is to make driving safer and to facilitate driving to the full extent, even on dangerous roads. However, having effective and robust operations within the VC system needs an infrastructure to handle threats, faults, illegitimate activities and unexpected incidents. Message authentication, integrity, non-repudiation and privacy within such a system are considered as the most controversial issues from security perspective. The idea is to protect privacy not only from legal point of view, but also from technical perspective in terms of using privacy enhancing technologies. To provide security within such a system, the idea of Public Key Infrastructure is considered as a promising solution. Using long-term certificates does reveal the real identity of the owner. Since users’ privacy is considered as the main security requirement in the VC system, standard certificates (X.509) and normal PKI cannot be used within a VC network. There are some functionalities and features for vehicular communication systems that do not exist in standard PKI. As a result, using pseudonym certificates to perform transactions within the VC system is a solution. In this report, a vehicular public key infrastructure, called VPKI, is proposed. OpenCA is used as the PKI, equipped with Pseudonym Certificate Authority (PCA), Long-Term Certificate Authority (LTCA) and Pseudonym Resolution Authority (PRA). These authorities are certified by the RCA and they have privileges to perform their tasks. LTCA is responsible for issuing long-term certificates while PCA is responsible for issuing pseudonym certificates. PRA is the authority to perform pseudonym resolution to identify the real identity of a pseudonym certificate. When it comes to CRL, PCA is the responsible authority to determine revoked pseudonym certificates in order to keep the system secure. Three protocols are then proposed to obtain pseudonym certificates, latest version of pseudonym CRL as well as performing pseudonym resolution. Obtaining pseudonym certificates is done in two phases. Firstly, each vehicle sends a request to LTCA to get a valid token. In the second step, the token is used by PCA to issue pseudonym certificates.
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Mousa, Farag. "Secure visible light communication systems based on the position of the user." Thesis, Northumbria University, 2017. http://nrl.northumbria.ac.uk/36262/.
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In the past few decades, there has been a growing demand for bandwidth in wireless communication systems due to an increase in the number of mobile users, computer network applications and high speed internet access and services. Visible light communication (VLC) is a newly emerging technology in optical wireless communication (OWC) systems to provide both illumination and high-speed data communication. In addition, it can also be used for indoor positioning or localization with wide applications that has merited a number of attractive research studies. However, security in wireless communications has become a matter of concern due to the possibility of unauthorised access to transmitted data. This thesis investigates received optical power (ROP) distribution to achieve illumination requirements for both optimal and sub-optimal Lambertian order in single and four cell configurations. Furthermore, it proposes VLC-based indoor positioning by using the received optical power levels from the emitting LEDs. Both scenarios of line-of-sight (LOS) and line-of-sight with non-line-of-sight (LOSNLOS) positioning are considered. The performance of the proposed system is evaluated under both noisy and noiseless channel cases and the impact of different location codes on the positioning error is also investigated. An analytical model of the system with noise and the corresponding numerical evaluation for a range of signal to noise ratios (SNRs) are presented. The results show that an accuracy of 8 cm in average is achievable at an SNR of 15 dB in the LOSNLOS scenario. We also introduce a novel approach for recovering 4×4 MIMO–VLC data with partial channel state information (CSI) knowledge both in noisy and noiseless cases. In addition, the proposed indoor localization system utilizing two visible light emitting diodes for different environments offering less complexity for both LOS and LOSNLOS scenarios is offered. The results of the scheme is compared with existing trilateration techniques and the performance of the proposed system is evaluated with a reported accuracy of less than 20 cm for SNR values of greater than 13 dB. This thesis also proposes a new secure single input single output (SISO) VLC system and investigates the bit error rate (BER) performance with and without encryption in the Media Access Control (MAC) layer and physical layer for both the LOS and LOSNLOS scenarios. For a BER of 10-3, the results show that there is 1 to ~ 3.5 dB power penalties for the secured VLC system for data rates of up to 10 Mbps. The key length impact on the error propagation is also investigated. Finally, this thesis proposes a secure MIMO VLC system that relies on the position of the user by incorporating a new modified version of the Rivest-Shamir-Adleman (RSA) technique for encrypting the transmitted data in the MAC layer. Furthermore, the ability of the proposed system to control the size of the encrypted cell depending on the application environment is demonstrated.
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Khodaei, Mohammad. "Secure and Privacy Preserving Vehicular Communication Systems: Identity and Credential Management Infrastructure." Licentiate thesis, KTH, Kommunikationsnät, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-193030.
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Vehicular Communication (VC) systems can greatly enhance road safety and transportation efficiency. Vehicles are equipped with sensors to sense their surroundings and the internal Controller Area Network (CAN) bus. Hence, vehicles are becoming part of a large-scale network, the so-called Internet of Vehicles (IoV). Deploying such a large-scale VC system cannot materialize unless the VC systems are secure and do not expose their users’ privacy. Vehicles could be compromised or their sensors become faulty, thus disseminating erroneous information across the network. Therefore, participating vehicles should be accountable for their actions. Moreover, user privacy is at stake: vehicles should disseminate spatio-temporal information frequently. Due to openness of the wireless communication, an observer can eavesdrop the communication to infer users’ sensitive information, thus profiling users. The objective is to secure the communication, i.e., prevent malicious or compromised entities from affecting the system operation, and ensure user privacy, i.e., keep users anonymous to any external observer but also for security infrastructure entities and service providers.In this thesis, we focus on the identity and credential management infrastructure for VC systems, taking security, privacy, and efficiency into account. We begin with a detailed investigation and critical survey of the standardization and harmonization efforts. We point out the remaining challenges to be addressed in order to build a Vehicular Public-Key Infrastructure (VPKI). We provide a VPKI design that improves upon existing proposals in terms of security and privacy protection and efficiency. More precisely, our scheme facilitates multi-domain operations in VC systems and enhances user privacy, notably preventing linking of pseudonyms based on timing information and offering increased protection in the presence of honest-but-curious VPKI entities. We further extensively evaluate the performance of the full-blown implementation of our VPKI for a large-scale VC deployment. Our results confirm the efficiency, scalability and robustness of our VPKI.<br><p>QC 20160927</p>
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Schneck, Phyllis Adele. "Dynamic management of computation and communication resources to enable secure high-performances applications." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/8264.
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Alotaibi, Hind. "Context-aware and secure workflow systems." Thesis, De Montfort University, 2012. http://hdl.handle.net/2086/8052.
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Businesses do evolve. Their evolution necessitates the re-engineering of their existing "business processes”, with the objectives of reducing costs, delivering services on time, and enhancing their profitability in a competitive market. This is generally true and particularly in domains such as manufacturing, pharmaceuticals and education). The central objective of workflow technologies is to separate business policies (which normally are encoded in business logics) from the underlying business applications. Such a separation is desirable as it improves the evolution of business processes and, more often than not, facilitates the re-engineering at the organisation level without the need to detail knowledge or analyses of the application themselves. Workflow systems are currently used by many organisations with a wide range of interests and specialisations in many domains. These include, but not limited to, office automation, finance and banking sector, health-care, art, telecommunications, manufacturing and education. We take the view that a workflow is a set of "activities”, each performs a piece of functionality within a given "context” and may be constrained by some security requirements. These activities are coordinated to collectively achieve a required business objective. The specification of such coordination is presented as a set of "execution constraints” which include parallelisation (concurrency/distribution), serialisation, restriction, alternation, compensation and so on. Activities within workflows could be carried out by humans, various software based application programs, or processing entities according to the organisational rules, such as meeting deadlines or performance improvement. Workflow execution can involve a large number of different participants, services and devices which may cross the boundaries of various organisations and accessing variety of data. This raises the importance of _ context variations and context-awareness and _ security (e.g. access control and privacy). The specification of precise rules, which prevent unauthorised participants from executing sensitive tasks and also to prevent tasks from accessing unauthorised services or (commercially) sensitive information, are crucially important. For example, medical scenarios will require that: _ only authorised doctors are permitted to perform certain tasks, _ a patient medical records are not allowed to be accessed by anyone without the patient consent and _ that only specific machines are used to perform given tasks at a given time. If a workflow execution cannot guarantee these requirements, then the flow will be rejected. Furthermore, features/characteristics of security requirement are both temporal- and/or event-related. However, most of the existing models are of a static nature – for example, it is hard, if not impossible, to express security requirements which are: _ time-dependent (e.g. A customer is allowed to be overdrawn by 100 pounds only up-to the first week of every month. _ event-dependent (e.g. A bank account can only be manipulated by its owner unless there is a change in the law or after six months of his/her death). Currently, there is no commonly accepted model for secure and context-aware workflows or even a common agreement on which features a workflow security model should support. We have developed a novel approach to design, analyse and validate workflows. The approach has the following components: = A modelling/design language (known as CS-Flow). The language has the following features: – support concurrency; – context and context awareness are first-class citizens; – supports mobility as activities can move from one context to another; – has the ability to express timing constrains: delay, deadlines, priority and schedulability; – allows the expressibility of security policies (e.g. access control and privacy) without the need for extra linguistic complexities; and – enjoy sound formal semantics that allows us to animate designs and compare various designs. = An approach known as communication-closed layer is developed, that allows us to serialise a highly distributed workflow to produce a semantically equivalent quasi-sequential flow which is easier to understand and analyse. Such re-structuring, gives us a mechanism to design fault-tolerant workflows as layers are atomic activities and various existing forward and backward error recovery techniques can be deployed. = Provide a reduction semantics to CS-Flow that allows us to build a tool support to animate a specifications and designs. This has been evaluated on a Health care scenario, namely the Context Aware Ward (CAW) system. Health care provides huge amounts of business workflows, which will benefit from workflow adaptation and support through pervasive computing systems. The evaluation takes two complementary strands: – provide CS-Flow’s models and specifications and – formal verification of time-critical component of a workflow.
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Lim, Yu-Xi. "Secure Geolocation for Wireless Indoor Networks." Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11454.
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The objective of the research is to develop an accurate system for indoor location
estimation using a secure architecture based on the IEEE 802.11 standard for infrastructure
networks. Elements of this secure architecture include: server-oriented
platform for greater trust and manageability; multiple wireless network parameters
for improved accuracy; and Support Vector Regression (SVR) for accurate, high-resolution
estimates. While these elements have been investigated individually in
earlier research, none has combined them to a single security-oriented system. Thus
this research investigates the feasibility of using these elements together.
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Croft, Neil John. "Secure interoperation of wireless technologies." Diss., Pretoria : [s.n.], 2003. http://upetd.up.ac.za/thesis/available/etd-12072004-082613.
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Khadra, Anmar. "Impulsive control and synchronization of chaos-generating-systems with applications to secure communication." Thesis, Waterloo, Ont. : University of Waterloo, 2004. http://etd.uwaterloo.ca/etd/akhadra2004.pdf.
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Thesis (Ph.D.)--University of Waterloo, 2004.<br>"A thesis presented to the University of Waterloo in fulfillment of the thesis requirement for the degree of Doctor of Philosophy in Applied Mathematics". Includes bibliographical references. Also available on microfiche.
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Pozzobon, Oscar. "Secure location services : vulnerability analysis and provision of security in location systems /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18315.pdf.
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Albath, Julia Gerda Maria. "Energy efficient clustering and secure data aggregation in wireless sensor networks." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2008. http://scholarsmine.mst.edu/thesis/pdf/Albath_09007dcc805ab299.pdf.
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Thesis (Ph. D.)--Missouri University of Science and Technology, 2008.<br>Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed December 2, 2008) Includes bibliographical references.
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Andersson, Martin. "Parametric Prediction Model for Perceived Voice Quality in Secure VoIP." Thesis, Linköpings universitet, Informationskodning, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-127402.
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More and more sensitive information is communicated digitally and with thatcomes the demand for security and privacy on the services being used. An accurateQoS metric for these services are of interest both for the customer and theservice provider. This thesis has investigated the impact of different parameterson the perceived voice quality for encrypted VoIP using a PESQ score as referencevalue. Based on this investigation a parametric prediction model has been developedwhich outputs a R-value, comparable to that of the widely used E-modelfrom ITU. This thesis can further be seen as a template for how to construct modelsof other equipments or codecs than those evaluated here since they effect theresult but are hard to parametrise. The results of the investigation are consistent with previous studies regarding theimpact of packet loss, the impact of jitter is shown to be significant over 40 ms.The results from three different packetizers are presented which illustrates theneed to take such aspects into consideration when constructing a model to predictvoice quality. The model derived from the investigation performs well withno mean error and a standard deviation of the error of a mere 1:45 R-value unitswhen validated in conditions to be expected in GSM networks. When validatedagainst an emulated 3G network the standard deviation is even lower.v
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Knight, Joseph T. "Optical Communication (OpCom) using Visible Light Communication (VLC) to Securely Configure Embedded Systems." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1553618192441296.
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Yuan, Yi. "Resource allocation and secure communication design in simultaneous wireless information and power transfer systems." Thesis, Lancaster University, 2018. http://eprints.lancs.ac.uk/123627/.
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Radio frequency (RF) energy transfer techniques have been regarded as the key enabling solutions to supply continuous and stable energy for the energy-constrained wireless devices. Simultaneous wireless information and power transfer (SWIPT) has been developed as a more promising RF energy transfer technique since it enables wireless information and wireless energy to access users from a same transmitted signal. Therefore, SWIPT has received remarkable attention. This thesis provides an investigation on applications and security issues of this emerging technology in various wireless communication scenarios. First, this thesis examines the application of SWIPT to a multi-user cooperative network in which the amplify-and-forward (AF) relay protocol is employed at the multi-antenna relay. A power splitting (PS) receiver architecture is utilized at each destination node to implement energy harvesting (EH) and information decoding (ID) simultaneously. The aim of this chapter is to minimize the relay transmit power by jointly designing relay beamforming vectors and PS ratios based on channel uncertainty models. The non-convex problem is converted into a semidefinite programming (SDP) problem by using the semidefinite relaxation (SDR) approach. In addition, a rank-one proof presents that the solution generated by the relaxed problem is optimal to the original problem. Second, a security issue about the SWIPT system is investigated in a cooperative network in the presence of potential eavesdroppers. The AF relay protocol and a PS receiver architecture are adopted at the multi-antenna relay and the desired destination node, respectively. Based on the system setup and the assumption of perfect channel state information (CSI), a transmit power minimization problem combined with the secrecy rate and harvested energy constraints is proposed to jointly optimize the beamforming vector and the PS ratio. The proposed optimization problem is non-convex and hard to tackle due to the issues of the quadratic terms and the coupled variables. To deal with this non-convex problem, two algorithms are proposed. In the first algorithm case, the proposed problem can be globally solved by using a two-level optimization approach which involves the SDR method and the one-dimensional (1-D) line search method. In addition, a rank reduction theorem is introduced to guarantee the tightness of the relaxation of the proposed scheme. In the second algorithm case, the proposed problem can be locally solved by exploiting a low complexity iterative algorithm which is embedded in the sequential parametric convex approximation (SPCA) method. Furthermore, the proposed optimization problem is extended to the imperfect CSI case. Third, a secure communication case is studied in an underlay multiple-input multiple-output (MIMO) cognitive radio (CR) network where the secondary transmitter (ST) provides SWIPT to receivers. In this chapter, two uncertainty channel models are proposed. One is based on the assumption that the ST has the perfect channel knowledge of the secondary information receiver (SIR) and the imperfect channel knowledge of secondary energy receivers (SERs) and primary receivers (PUs). The other one assumes that the ST only has the imperfect channel knowledge of all receivers. In each uncertainty channel model, an outage-constrained secrecy rate maximization (OC-SRM) problem combined with probability constraints is proposed to jointly optimizing the transmit covariance matrix and the artificial noise (AN)- aided covariance matrix. The designed OC-SRM problem for both models is non-convex due to the unsolvable probabilistic constraints. To solve this non-convex problem, the log determinant functions are first approximated to the easy handle the functions that the channel error terms are included in the trace function. Then, the probability constraints are converted into the deterministic constraints by exploiting the Bernstein-type inequality (BTI) approach. Finally, the reformulated problem for both models is solvable by using the existing convex tools. Last, a novel security issue is investigated in a MIMO-SWIPT downlink network where nonlinear energy receivers (ERs) are considered as the potential eavesdroppers. In this chapter, two uncertainty channel models, namely partial channel uncertainty (PCU) and full channel uncertainty (FCU), are proposed. An OC-SRM problem of each model is proposed to design the transmit signal covariance matrix while satisfying probabilistic constraints of the secrecy rate and the harvested energy. To surmount the non-convexity of the proposed OC-SRM problem in each model, several transformations and approximations are utilized. In the PCU model, the OC-SRM problem is first converted into two subproblems by introducing auxiliary variables. Then, three conservative approaches are adopted to obtain the safe approximation expressions of the probabilistic constraints, which are deterministic constraints. Moreover, an alternating optimization (AO) algorithm is proposed to iteratively solve two convex conic subproblems. In the FCU model, log determinant functions are first approximated to the trace functions. Then, the three approaches aforementioned are employed to convert probabilistic constraints into deterministic ones. The bisection method is utilized to solve the reformulated problem. Finally, the computational complexity of the proposed three approaches based on the PCU and FCU model is analyzed.
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Morrow, Shenae Y. "Automated messaging for the Global Command and Control System : analysis of upgrading communications in the NPS Secure Systems Technology Laboratory (SSTL) /." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1996. http://handle.dtic.mil/100.2/ADA327126.
Full textAbstract:
Thesis (M.S. in Information Technology Management) Naval Postgraduate School, September 1996/<br>Thesis advisor(s): Gary Porter, Carl R. Jones. "September 1996." Includes bibliographical references (p. 55-56). Also Available online.
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CHEN, JIAN. "THE DESIGN OF NONLINEAR TIME VARYING SYSTEMS AND THEIR SYNCHRONIZED SYSTEMS FOR APPLICATION IN SECURE DIGITAL COMMUNICATION." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1077849064.
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Wiss, Thomas. "Evaluation of Internet of Things Communication Protocols Adapted for Secure Transmission in Fog Computing Environments." Thesis, Mittuniversitetet, Avdelningen för informationssystem och -teknologi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-35298.
Full textAbstract:
A current challenge in the Internet of Things is the seeking after conceptual structures to connect the presumably billions of devices of innumerable forms and capabilities. An emerging architectural concept, the fog cloud computing, moves the seemingly unlimited computational power of the distant cloud to the edge of the network, closer to the potentially computationally limited things, effectively diminishing the experienced latency. To allow computationally-constrained devices partaking in the network they have to be relieved from the burden of constant availability and extensive computational execution. Establishing a publish/subscribe communication pattern with the utilization of the popular Internet of Things application layer protocol Constrained Application Protocol is depicted one approach of overcoming this issue. In this project, a Java based library to establish a publish/subscribe communication pattern for the Constrained Application Protocol was develop. Furthermore, efforts to build and assess prototypes of several publish/subscribe application layer protocols executed over varying common as well as secured versions of the standard and non-standard transport layer protocols were made to take advantage, evaluate, and compare the developed library. The results indicate that the standard protocol stacks represent solid candidates yet one non-standard protocol stack is the considered prime candidate which still maintains a low response time while not adding a significant amount of communication overhead.
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Tsai, Chi Cheng, and 蔡奇璋. "A Secure Telewriter for Personal Communication System." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/14734797412134459316.
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Huang, Pai-Yi, and 黃柏儀. "A Secure Communication System Based on FPGA circuit." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/20770972549724877387.
Full textAbstract:
碩士<br>國立雲林科技大學<br>電機工程系碩士班<br>91<br>To develop the secure communication system is a popular information
industry, however how to promote the property and raise the security of
information is a mainly concerned in this thesis. In the study, we use the
characteristic of chaos to modulate the transmission signal combine the
concept of chaos synchronization control to establish a secure
communication system.
The idea of secure communication system is utilized chaotic signals to
mask or modulate the transmitter signal, thus guarantees that the message
can’t usurp during transmitting process. Based on nonlinear observer theory,
the observer gain can be obtained to that transmitter and receiver can be
achieved asymptotical, dead-beat or generalizaed synchronization.
Furthermore, we discuss how to design a controller by adaptive
backstepping technique, or employ the E.K.F adaptive law to estimate the
parameters and states of system. Therefore master-slave systems can be
achieved the so-called adaptive synchronization, when the system
parameters are unknown. Finally, some numerical simulations are given to
demonstrate that the method is feasible in secure communication.
Finally, we use CADs of digital system are completely, implement a
Henon system generator and a observer on FPGA chip. And the results is
feasible.
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Chen, Wan-tai, and 陳萬泰. "A Message Secure Communication System Based on DSP." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/16237261435914286479.
Full textAbstract:
碩士<br>國立雲林科技大學<br>電機工程系碩士班<br>91<br>In this thesis, we develop a message secure communication system based on digital signal processing. By using the methods of adaptive control and the skills of cryptography, the message transmitting in the public channel can’t be retrieved by intruder.
There are two parts by using different control methods in this thesis. In the first part, SPR-Lyapunov algorithm is used to design a adaptive law for Chua’s-hyperchaotic circuit and Lorenz-hyperchaotic circuit respectively. Therefore, the synchronization of master and slave can be achieved under system parameter unknown. In the second part, the chaotic synchronization using extended Kalman filter is derived.
By using the adaptive algorithm, a bidirectional adaptive secure communication systems are obtained by the well known chaotic circuits. The numerical simulation results are given to demonstrate that the proposed scheme is effect and validity. Finally, we realize the schemes by using DSP chip and demonstrate the scheme can be worked efficiently.
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Qiu, D. L., and 邱東樑. "Bi-directional Secure communication system via chaotic circuit." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/09814328835624451342.
Full textAbstract:
碩士<br>國立雲林科技大學<br>電機工程系碩士班<br>90<br>There are three topics that are studied in this thesis. In the first topic, we emphasize on the so-called synchronization. By the Lyapunov stability theorem, a state feedback gain can be designed to guarantee the synchronization between the master and slave chaotic systems.
In the second topic, the concept of the cryptology is used to enhance the performance of security in the communication by the chaotic circuits.
In the third topic , we studied how to design an adative controller for hyperchaotic circuits with unknown parameters. By using the concepts of PR or hyper-minimum-phase, the adaptive controller and adaptive law can be designed. Further- more, the concepts cryptography and adaptive control law are combined to design an adaptive cryptosystem.
Finally, some numerical simulations and the fabrication of the chaotic circuits were given to demonstrate the efficiency of the proposed scheme.