1,983 research outputs found

    POWER-SUPPLaY: Leaking Data from Air-Gapped Systems by Turning the Power-Supplies Into Speakers

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    It is known that attackers can exfiltrate data from air-gapped computers through their speakers via sonic and ultrasonic waves. To eliminate the threat of such acoustic covert channels in sensitive systems, audio hardware can be disabled and the use of loudspeakers can be strictly forbidden. Such audio-less systems are considered to be \textit{audio-gapped}, and hence immune to acoustic covert channels. In this paper, we introduce a technique that enable attackers leak data acoustically from air-gapped and audio-gapped systems. Our developed malware can exploit the computer power supply unit (PSU) to play sounds and use it as an out-of-band, secondary speaker with limited capabilities. The malicious code manipulates the internal \textit{switching frequency} of the power supply and hence controls the sound waveforms generated from its capacitors and transformers. Our technique enables producing audio tones in a frequency band of 0-24khz and playing audio streams (e.g., WAV) from a computer power supply without the need for audio hardware or speakers. Binary data (files, keylogging, encryption keys, etc.) can be modulated over the acoustic signals and sent to a nearby receiver (e.g., smartphone). We show that our technique works with various types of systems: PC workstations and servers, as well as embedded systems and IoT devices that have no audio hardware at all. We provide technical background and discuss implementation details such as signal generation and data modulation. We show that the POWER-SUPPLaY code can operate from an ordinary user-mode process and doesn't need any hardware access or special privileges. Our evaluation shows that using POWER-SUPPLaY, sensitive data can be exfiltrated from air-gapped and audio-gapped systems from a distance of five meters away at a maximal bit rates of 50 bit/sec

    Indoor gigabit optical wireless communications: challenges and possibilities

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    Indoor Gigabit optical wireless communication systems have the potential to offer multiple high-speed data services that can be delivered to homes via an optical fibre cable in the near future. In this paper we will discuss the challenges involved in the design of such systems and future possible advances. Results from a recent cellular Gigabit prototype link will also be presented and discussed

    A Review of Commercial Electric Vehicle Charging Methods

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    Electric Vehicles (EVs) are rapidly becoming the forerunners of vehicle technology. First electric vehicles were overlooked because of not having adequate battery capacity and because of low efficiency of their electric motors. Developing semiconductor and battery technologies increased the interest in the EVs. Nevertheless, current batteries still have insufficient capacity. As a result of this, vehicles must be recharged at short distances (approximately 150 km). Due to scheduled departure and arrival times EVs appear to be more suitable for city buses rather than regular automobiles. Thanks to correct charging technology and the availability of renewable energy for electric buses, the cities have less noise and CO2 emissions. The energy consumption of internal combustion engines is higher than of the electric motors. In this paper, studies on the commercial electric vehicle charging methods will be reviewed and the plug-in charging processes will be described in detail. This study strives to answer the questions of how plug-in charging process communication has performed between the EV and Electric Vehicle Supply Equipment (EVSE).</p

    Underwater Optical Wireless Audio Transceiver

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    Scuba diving carries risks that can endanger lives. Many of these risks are preventable. However, an underwater communication system can increase a diver’s safety. Along with providing safety, an underwater communication device can enhance the scuba diver’s enjoyment. A low cost underwater optical wireless audio transceiver is designed. The project consists of the off-the-shelf parts that uses a microphone and speaker to transmit and receive sound. The project uses the concepts of visible light communications and pulse width modulation to transmit and receive sound. Although sound is commonly transmitted through ultrasound methods, visible light communications has several advantages. Visible light communications have higher bandwidth capability, suffer no electromagnetic interference, and travel at the speed of light. It also has its limitations including short ranges and line of sight. Fortunately, there is a small window in the blue-green region that is not heavily absorbed by water. The final prototype of the project is non-functional. However, there are possible fixes that could improve the project’s performance such as higher powered LEDs and collimating lens to focus the light to the receiver

    Intentional Electromagnetic Interference Attack on Sensors and Actuators

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    Embedded systems are critically relying on the integrity its input and output signals to ensure proper operation. Signal from sensors, either analog or digital, are blindly trusted by the embedded systems, to estimate the environment, in which the system is set to monitor and respond to. Similarly, actuators, that are connected to and controlled by an embedded system, are expected to behave in a reliable manner, to perform a particular physical motion. However, recent publications, from hardware security researchers, have shown that sensor signals can be manipulated by injection of false data, using intentional electromagnetic interference (IEMI). In this work, the author proves that both the input as well as the output signals of an embedded system are vulnerable to data manipulation, via physical layer of this system, which would bypass any traditional defense mechanism. By using specially crafted IEMI attack techniques, this work has shown that the physical layer input/ output signals can be manipulated by an attacker, thereby providing the attacker, with the ability to remotely control an embedded system. Three different attack scenarios had been analyzed and the effectiveness of the attack against each scenario has been experimentally verified. First, an embedded system, gathering data through an analog sensor, was manipulated to output arbitrary sensor data, while in the second scenario, a slightly modified attack technique, has been shown to successfully inject false data into digital communication lines. Finally, commonly used digital actuators, which were controlled by embedded system, has been shown as a potential target for false data injection attack, using IEMI techniques. These attacks have been shown to be effective, at appreciable distances from the victim circuit, while using attack signals with relatively less power

    Investigation of high bandwith biodevices for transcutaneous wireless telemetry

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    PhD ThesisBIODEVICE implants for telemetry are increasingly applied today in various areas applications. There are many examples such as; telemedicine, biotelemetry, health care, treatments for chronic diseases, epilepsy and blindness, all of which are using a wireless infrastructure environment. They use microelectronics technology for diagnostics or monitoring signals such as Electroencephalography or Electromyography. Conceptually the biodevices are defined as one of these technologies combined with transcutaneous wireless implant telemetry (TWIT). A wireless inductive coupling link is a common way for transferring the RF power and data, to communicate between a reader and a battery-less implant. Demand for higher data rate for the acquisition data returned from the body is increasing, and requires an efficient modulator to achieve high transfer rate and low power consumption. In such applications, Quadrature Phase Shift Keying (QPSK) modulation has advantages over other schemes, and double the symbol rate with respect to Binary Phase Shift Keying (BPSK) over the same spectrum band. In contrast to analogue modulators for generating QPSK signals, where the circuit complexity and power dissipation are unsuitable for medical purposes, a digital approach has advantages. Eventually a simple design can be achieved by mixing the hardware and software to minimize size and power consumption for implantable telemetry applications. This work proposes a new approach to digital modulator techniques, applied to transcutaneous implantable telemetry applications; inherently increasing the data rate and simplifying the hardware design. A novel design for a QPSK VHDL modulator to convey a high data rate is demonstrated. Essentially, CPLD/FPGA technology is used to generate hardware from VHDL code, and implement the device which performs the modulation. This improves the data transmission rate between the reader and biodevice. This type of modulator provides digital synthesis and the flexibility to reconfigure and upgrade with the two most often languages used being VHDL and Verilog (IEEE Standard) being used as hardware structure description languages. The second objective of this thesis is to improve the wireless coupling power (WCP). An efficient power amplifier was developed and a new algorithm developed for auto-power control design at the reader unit, which monitors the implant device and keeps the device working within the safety regulation power limits (SAR). The proposed system design has also been modeled and simulated with MATLAB/Simulink to validate the modulator and examine the performance of the proposed modulator in relation to its specifications.Higher Education Ministry in Liby

    The effect of EMI generated from spread-spectrum modulated converters on the power line communication systems

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    Over the last few years, the smart grid and renewable energy environment have attracted heightened interest and relevance from governments and investors for the purpose of decreasing their dependency on fossil fuels as a source of energy. Consequently, the dependency on the power converters and the communication systems continues to rise in order to link the grid elements with each other, thereby creating a complex environment. As such, one of the challenges resulting from this ‘complex’ environment is the Electromagnetic Compatibility (EMC) between the smart grid devices. In most cases, the power converter’s modulation is the main source of emissions in the smart grid. Thus, the focus of this thesis remains only on the conducted emissions in the low-frequency range. The EMC standards deal with managing the amplitude of the emissions generated from the devices at any given frequency range. A great many studies have been interested in the use of Spread-Spectrum modulation (SSM) as an Electromagnetic Interference (EMI) amplitude mitigation tool. Notably, the communication systems operating in the smart grid are the main victim, as most of the power converters switching modulation frequencies lay in the same frequency range as the communication systems.The SSM works to distribute the signal power by randomizing the modulation parameters. The PLC system works by the OFDM modulation, which works also by distributing the communication signal to several sub-carriers. To meet the research needs, a proposed testbed is implemented to couple both the power and the communication circuit. The performance of the communication system is analysed under several various operating scenarios using two approaches to assure the robustness of the results— (1) measuring the Frame Error Rate (FER) throughout the communication channel, and; (2) calculating the channel capacity of the used channel by the Shannon Hartley equation. In conclusion, the purpose of the thesis is to assure the robustness of the power line communication data transmission capability by controlling the modulation parameters of power electronic converters working in nearby electromagnetic environments

    Wireless Sensors and Actuators for Structural Health Monitoring of Fiber Composite Materials

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    This work evaluates and investigates the wireless generation and detection of Lamb-waves on fiber-reinforced materials using surface applied or embedded piezo elements. The general target is to achieve wireless systems or sensor networks for Structural Health Monitoring (SHM), a type of Non-Destructive-Evaluation (NDE). In this sense, a fully wireless measurement system that achieves power transmission implementing inductive coils is reported. This system allows a reduction of total system weight as well as better integration in the structure. A great concern is the characteristics of the material, in which the system is integrated, because the properties can have a direct impact on the strength of the magnetic field. Carbon-Fiber-Reinforced-Polymer (CFRP) is known to behave as an electrical conductor, shielding radio waves with increasing worse effects at higher frequencies. Due to the need of high power and voltage, interest is raised to evaluate the operation of piezo as actuators at the lower frequency ranges. To this end, actuating occurs at the International Scientific and Medical (ISM) band of 125 kHz or low-frequency (LF) range. The feasibility of such system is evaluated extensively in this work. Direct excitation, is done by combining the actuator bonded to the surface or embedded in the material with an inductive LF coil and setting the circuit in resonance. A more controlled possibility, also explored, is the use of electronics to generate a Hanning-windowed-sine to excite the PWAS in a narrow spectrum. In this case, only wireless power is transmitted to the actuator node, and this lastly implements a Piezo-driver to independently excite Lamb-waves. Sensing and data transfer, on the other hand, is done using the high-frequency (HF) 13.56 MHz. The HF range covers the requirements of faster sampling rate and lower energy content. A re-tuning of the antenna coils is performed to obtain better transmission qualities when the system is implemented in CFRP. Several quasi-isotropic (QI) CFRP plates with sensor and actuator nodes were made to measure the quality of transmission and the necessary energy to stimulate the actuator-sensor system. In order to produce baselines, measurements are prepared from a healthy plate under specific temperature and humidity conditions. The signals are evaluated to verify the functionality in the presence of defects. The measurements demonstrate that it is possible to wirelessly generate Lamb-waves while early results show the feasibility to determine the presence of structural failure. For instance, progress has been achieved detecting the presence of a failure in the form of drilled holes introduced to the structure. This work shows a complete set of experimental results of different sensor/-actuator nodes

    Wireless Power Transfer

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    Wireless power transfer techniques have been gaining researchers' and industry attention due to the increasing number of battery-powered devices, such as mobile computers, mobile phones, smart devices, intelligent sensors, mainly as a way to replace the standard cable charging, but also for powering battery-less equipment. The storage capacity of batteries is an extremely important element of how a device can be used. If we talk about battery-powered electronic equipment, the autonomy is one factor that may be essential in choosing a device or another, making the solution of remote powering very attractive. A distinction has to be made between the two forms of wireless power transmission, as seen in terms of how the transmitted energy is used at the receiving point: - Transmission of information or data, when it is essential for an amount of energy to reach the receiver to restore the transmitted information; - Transmission of electric energy in the form of electromagnetic field, when the energy transfer efficiency is essential, the power being used to energize the receiving equipment. The second form of energy transfer is the subject of this book
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