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The ubiquitous interconnectivity of electronic devices offered by Internet-of-Things (IoT) networks has been increasingly embraced in a wide range of applications. In IoT networks, threats to hardware security are often not perceived as serious, with the assumption that an attack could only be carried out at close proximity. However, in this article, we show that through electromagnetic (EM) side-channel signal leakage, operational information and program activities of IoT devices and field-programmable gate array (FPGA) modules can be garnered from approximately 200 m away in an outdoor line-of-sight (LOS) environment. We describe an extensive measurement campaign conducted to investigate the aforementioned leakage and provide propagation models that can be used to predict the power (and corresponding variation i.e., shadowing gain) of the EM side-channel signal emanation at various distances, scenarios, and environments. With a circularly polarized receiver antenna, our results show that the received power of the emanated EM side-channel (carrier) signal varies from about −61 dBm at 1 m to about −112 dBm at 200 m in the outdoor LOS environment. Furthermore, a received signal power of about −73 dBm was observed at 1 m and −88 dBm was recorded at 10 m in an indoor LOS environment. Power variation (shadowing gain) of about 3.6 and 2.0 dB was observed in the outdoor and indoor environments, respectively. This work is relevant for EM side-channel leakage countermeasure development and provides pertinent information to embedded systems and wireless network security engineers. [ABSTRACT FROM AUTHOR]

This article presents characterization of terahertz (THz) wireless channel inside a desktop size metal enclosure with the consideration of several different scenarios. Measurements indicate that both traveling wave and resonating modes exist inside the metal enclosure. Measurements for line-of-sight (LoS) propagation inside the empty metal enclosure show that the path loss significantly changes as a function of the transceiver’s height. It is found that this variation is due the resonant modes, contribution to the received power. Reflected-non-LoS (RNLoS) measurements show that for the same distance, the difference between the mean path loss measured inside the metal box and in a free space is limited to 1 dB, with traveling wave dominating the channel. This indicates that reflectors can be used as wave-guiding objects in metal enclosures. Finally, obstructed-LoS (OLoS) path loss measurements with the parallel dual in-line memory modules (DIMMs) as obstructions show the constructive/destructive effect on the waves due to multipath introduced by the parallel-plate structures. Compared to the free space scenarios, multipath is introduced by the traveling wave bouncing back and forth between the transceiver sides of the cavity, which introduces stronger fluctuations in observed pathloss and reduces the coherence bandwidth of the channel. [ABSTRACT FROM AUTHOR]

The goal of this paper is to answer how much information is “transmitted” by the execution of particular sequence of instructions in a processor. Introducing such a measure would provide quantitative guidance for designing programs and computer hardware that minimizes inadvertent (side channel) information leakage, and would also help detect parts of a program or hardware design that have unusually high leakage (i.e., were designed to function as covert channel “transmitters”). To answer this question, we propose a new method to estimate the maximum information leakage through EM signals generated by the execution of instructions in a processor. We start by deriving a mathematical relationship between electromagnetic side-channel energy of individual instructions and the measured pairwise side-channel signal power. Then, we use this measure to calculate the transition probabilities needed for estimating capacity. Finally, we propose a new method to estimate side/covert channel capacity created by the execution of instructions in a processor and illustrate our results in several computer systems. [ABSTRACT FROM PUBLISHER]

This paper presents characterization of 300-GHz wireless channel on a computer motherboard, where several different measurement scenarios have been considered. Results indicate that the presence of the ground plane and/or vertical parallel-plate structures in the channel introduces multipath that, if constructively superimposed, may create a path loss lower than free-space propagation path loss. In addition, it has been found that a few centimeters of vertical misalignment between the transmitter and the receiver result in a path loss greater than 5 dB. Furthermore, the results indicate that vertical components such as dual in-line memory modules with reflection coefficient close to one for all incident angles can be used to create directed non-line-of-sight (LoS) links with wide coherence bandwidth. Finally, for LoS propagation obstructed by large objects, such as a heatsink, the path-loss exponent of 1.77 is found, while the rotating fan causes periodic fading in the received power, indicating that channel equalization techniques will be needed to overcome deep fades. All these results indicate that optimal communications can be achieved by carefully positioning the antennas with respect to the motherboard layout. [ABSTRACT FROM PUBLISHER]

This paper presents measurements and statistical characterization of 300- to 320-GHz desktop channels. The measurements are performed in line-of-sight (LoS) and non-LoS (NLoS) environments. From the large set of LoS measured data, the parameters for the single-slope path-loss model with shadowing are devised. The results show that the path-loss exponent is around 1.9 and that the variations due to shadowing are similar across different frequencies and different bandwidths. Furthermore, the impact of different materials on the path loss is studied in the NLoS environment. The results show that metal objects in the propagation path cause multiple strong reflections, leading to a higher path loss. Furthermore, the statistical analysis of multipath propagation is performed. The root-mean-square (RMS) delay spread, the mean excess delay, the maximum excess delay, and the coherence bandwidth for LoS and NLoS environments are calculated. The results show that the mean excess delay and RMS delay spread increase with distance and that the RMS delay spread in the desktop terahertz channel is much smaller than that in typical indoor ultrawideband channels. In addition, the power delay profiles for LoS and NLoS environments are analyzed. The results show that strong reflections from the transmitter and receiver electronics are present in both LoS and NLoS environments. Finally, the statistical analysis of the measured signal amplitude in LoS and NLoS environments is performed. For both LoS and NLoS propagation environments, it is found that the lognormal distribution provides the best fit. [ABSTRACT FROM PUBLISHER]

This paper presents measurements and characterization of D-band indoor channels. The measurements are performed in line-of-sight (LoS), obstructed-LoS (OLoS), and reflected non-LoS (RNLoS) environments. For OLoS sceanrio, cylindrical objects of different materials are used as an obstruction. For RNLoS, different surfaces are used as reflectors. From the large set of LoS and OLoS measured data, the parameters for single-slope path loss model with shadowing are devised. Furthermore, the analysis of multipath propagation is performed. The results show that strong multiple reflections from the transmitter and receiver electronics are present both in LoS and OLoS environments. Additionally, the results show that glass and ceramic objects in the propagation path produce surface-diffracted rays which clock-wise and counter clock-wise superposition leads to frequency-dependent path loss. Finally, the results show that the RNLoS measured path loss with aluminum plate as a reflector is very similar to free-space path loss when the angle of incidence and the angle of reflection are equal. [ABSTRACT FROM PUBLISHER]