Biblio

This paper investigates the robustness of the received signal strength (RSS)-based physical layer authentication (PLA) for wireless mesh networks, through experimental results. Specifically, we develop a secure wireless mesh networking framework and apply the RSS-based PLA scheme, with the aim to perform continuous authentication. The mesh setup comprises three Raspberry-PI4 computing nodes (acting as Alice, Bob, and Eve) and a server. The server role is to perform the initial authentication when a new node joins the mesh network. After that, the legitimate nodes in the mesh network perform continuous authentication, by leveraging the RSS feature of wireless signals. In particular, Bob tries to authenticate Alice in the presence of Eve. The performance of the presented framework is quantified through extensive experimental results in an outdoor environment, where various nodes' positions, relative distances, and pedestrian speeds scenarios are considered. The obtained results demonstrate the robustness of the underlying model, where an authentication rate of 99% for the static case can be achieved. Meanwhile, at the pedestrian speed, the authentication rate can drop to 85%. On the other hand, the detection rate improves when the distance between the legitimate and wiretap links is large (exceeds 20 meters) or when Alice and Eve are moving in different mobility patterns.

The electron mobility μ exhibits oscillatory behavior with gate electric field F in an asymmetrically doped double V-shaped AlxGa1-xAs quantum well field effect transistor structure. By changing F, single-double-single subband occupancy of the system is obtained. We show that μ oscillates within double subband occupancy as a function of F near resonance of subband states due to the relocation of subband wave functions between the wells through intersubband effects.

Common randomness of channels offers the possibility to create cryptographic keys without the need for a key exchange procedure. Channel reciprocity for TDD (time-division duplexing) systems has been used for this purpose many times. FDD (frequency-division duplexing) systems, however, were long considered to not provide any usable symmetry. However, since the scattering transmission parameters S\textbackslashtextlessinf\textbackslashtextgreater12\textbackslashtextless/inf\textbackslashtextgreater and S\textbackslashtextlessinf\textbackslashtextgreater21\textbackslashtextless/inf\textbackslashtextgreater would ideally be the same due to reciprocity, when using neighboring frequency ranges for both directions, they would just follow a continuous curve when putting them next to each other. To not rely on absolute phase, we use phase differences between antennas and apply a polynomial curve fitting, thereafter, quantize the midpoint between the two frequency ranges with the two measurement directions. This is shown to work even with some spacing between the two bands. For key reconciliation, we force the measurement point from one direction to be in the midpoint of the quantization interval by a grid shift (or likewise measurement data shift). Since the histogram over the quantization intervals does not follow a uniform distribution, some source coding / hashing will be necessary. The key disagreement rate toward an eavesdropper was found to be close to 0.5. Additionally, when using an antenna array, a random permutation of antenna measurements can even further improve the protection against eavesdropping.

Cyber ranges are valuable assets but have limitations in simulating complex realities and multi-sector dependencies; to address this, federated cyber ranges are emerging. This work presents the ECHO Federated Cyber Range, a marketplace for cyber range services, that establishes a mechanism by which independent cyber range capabilities can be interconnected and accessed via a convenient portal. This allows for more complex and complete emulations, spanning potentially multiple sectors and complex exercises. Moreover, it supports a semi-automated approach for processing and deploying service requests to assist customers and providers interfacing with the marketplace. Its features and architecture are described in detail, along with the design, validation and deployment of a training scenario.

Despite the high directivity of THz beams, THz wireless links may still suffer compromising emissions when propagate through atmospheric turbulence and suffers scattering. In this work, we investigate the eavesdropping risks of a line-of-sight (LOS) THz link `in atmospheric turbulence with an eavesdropper located close to but outside of the beam path. A theoretical model considering the turbulence induced losses, gaseous absorption and beam divergence is conducted. Theoretical estimations agree well with our measured data. The secrecy capacity and outage probability dependent on the carrier frequency, turbulence strength, eavesdropper’s position and receiver sensitivity are analyzed.

Millimeter wave imaging radar is indispensible for collision avoidance of self-driving system, especially in optically blurred visions. The range points migration (RPM) is one of the most promising imaging algorithms, which provides a number of advantages from synthetic aperture radar (SAR), in terms of accuracy, computational complexity, and potential for multifunctional imaging. The inherent problem in the RPM is that it suffers from lower angular resolution in narrower frequency band even if higher frequency e.g. millimeter wave, signal is exploited. To address this problem, the k-space decomposition based RPM has been developed. This paper focuses on the experimental validation of this method using the X-band or millimeter wave radar system, and demonstrated that our method significantly enhances the reconstruction accuracy in three-dimensional images for the two simple spheres and realistic vehicle targets.

In-Band Full-Duplex (IBFD) Underwater Acoustic (UWA) communication technology plays a major role in enhancing the performance of Underwater acoustic sensor networks (UWSN). Self-Interference (SI) is one of the main inherent challenges affecting the performance of IBFD UWA communication. To reconstruct the SI signal and counteract the SI effect, this is important to estimate the short range channel through which the SI signal passes. Inaccurate estimation will result in the performance degradation of IBFD UWA communication. From the perspective of engineering implementation, we consider that the UWA communication modem shell has a significant influence on the short-range SI channel, which will limit the efficiency of self-interference cancellation in the analog domain to some degree. Therefore we utilize a simplified model to simulate the influence of the structure of the IBFD UWA communication modem on the receiving end. This paper studies the effect of acoustic-shell coupling on near-end self-interference signal of IBFD UWA communication modem. Some suggestions on the design of shell structure of IBFD UWA communication modem are given.

Summary form only given. Authentication of people or objects using physical keys is insecure against secret duplication. Physical unclonable functions (PUF) are special physical keys that are assumed to be unclonable due to the large number of degrees of freedom in their manufacturing [1]. Opaque scattering media, such as white paint and teeth, comprise of millions of nanoparticles in a random arrangement. Under coherent light illumination, the multiple scattering from these nanoparticles gives rise to a complex interference resulting in a speckle pattern. The speckle pattern is seemingly random but highly sensitive to the exact position and size of the nanoparticles in the given piece of opaque scattering medium [2], thereby realizing an ideal optical PUF. These optical PUFs enabled applications such as quantum-secure authentication (QSA) and communication [3, 4].

Analysis of acoustic wave scattering by a finite flat impedance strip grating is presented. The associated two-dimensional (2-D) boundary-value problem is considered in the full-wave manner and cast to a set of coupled integral equations. Based on them, we build several mathematical models. The focus of research is on the acoustic plane wave scattering by a grating of narrow impedance strips that has explicit asymptotic solution.

Cloud computing has become a widely used computing paradigm providing on-demand computing and storage capabilities based on pay-as-you-go model. Recently, many organizations, especially in the field of big data, have been adopting the cloud model to perform data analytics through leasing powerful Virtual Machines (VMs). VMs can be attractive targets to attackers as well as untrusted cloud providers who aim to get unauthorized access to the business critical-data. The obvious security solution is to perform data analytics on encrypted data through the use of cryptographic keys as that of the Advanced Encryption Standard (AES). However, it is very easy to obtain AES cryptographic keys from the VM's Random Access Memory (RAM). In this paper, we present a novel key-scattering (KS) approach to protect the cryptographic keys while encrypting/decrypting data. Our solution is highly portable and interoperable. Thus, it could be integrated within today's existing cloud architecture without the need for further modifications. The feasibility of the approach has been proven by implementing a functioning prototype. The evaluation results show that our approach is substantially more resilient to brute force attacks and key extraction tools than the standard AES algorithm, with acceptable execution time.