Deep Learning Methods for Device Identification Using Symbols Trace Plot

Devices authentication is one crucial aspect of any communication system. Recently, the physical layer approach radio frequency (RF) fingerprinting has gained increased interest as it provides an extra layer of security without requiring additional components. In this work, we propose an RF fingerprinting based transmitter authentication approach density trace plot (DTP) to exploit device-identifiable fingerprints. By considering IQ imbalance solely as the feature source, DTP can efficiently extract device-identifiable fingerprints from symbol transition trajectories and density center drifts. In total, three DTP modalities based on constellation, eye and phase traces are respectively generated and tested against three deep learning classifiers: the 2D-CNN, 2D-CNN+biLSTM and 3D-CNN. The feasibility of these DTP and classifier pairs is verified using a practical dataset collected from the ADALM-PLUTO software-defined radios (SDRs)

Performance Analysis of Transmitter Identification Based on I/Q Imbalance Estimation

Performance of a transmitter identification method based on I/Q imbalance estimation is analyzed for different modulation types in this work. This analysis is considered on the basis of the constellation structure of proper and improper modulation signals. The effect of impropriety of complex signals on the features obtained from I/Q imbalance is analyzed. Simulation results show that transmitters can be identified with a high accuracy for proper communication signals even at low SNR, whereas the identification performance degrades for improper communications signals, especially at low SNR. © 2019 IEEE

A robust, reliable and deployable framework for In-vehicle security

Cyber attacks on financial and government institutions, critical infrastructure, voting systems, businesses, modern vehicles, etc., are on the rise. Fully connected autonomous vehicles are more vulnerable than ever to hacking and data theft. This is due to the fact that the protocols used for in-vehicle communication i.e. controller area network (CAN), FlexRay, local interconnect network (LIN), etc., lack basic security features such as message authentication, which makes it vulnerable to a wide range of attacks including spoofing attacks. This research presents methods to protect the vehicle against spoofing attacks. The proposed methods exploit uniqueness in the electronic control unit electronic control unit (ECU) and the physical channel between transmitting and destination nodes for linking the received packet to the source. Impurities in the digital device, physical channel, imperfections in design, material, and length of the channel contribute to the uniqueness of artifacts. I propose novel techniques for electronic control unit (ECU) identification in this research to address security vulnerabilities of the in-vehicle communication. The reliable ECU identification has the potential to prevent spoofing attacks launched over the CAN due to the inconsideration of the message authentication. In this regard, my techniques models the ECU-specific random distortion caused by the imperfections in digital-to-analog converter digital to analog converter (DAC), and semiconductor impurities in the transmitting ECU for fingerprinting. I also model the channel-specific random distortion, impurities in the physical channel, imperfections in design, material, and length of the channel are contributing factors behind physically unclonable artifacts. The lumped element model is used to characterize channel-specific distortions. This research exploits the distortion of the device (ECU) and distortion due to the channel to identify the transmitter and hence authenticate the transmitter.Ph.D.College of Engineering & Computer ScienceUniversity of Michigan-Dearbornhttps://deepblue.lib.umich.edu/bitstream/2027.42/154568/1/Azeem Hafeez Final Disseration.pdfDescription of Azeem Hafeez Final Disseration.pdf : Dissertatio

Physical-Layer Authentication Using Channel State Information and Machine Learning

Strong authentication in an interconnected wireless environment continues to be an important, but sometimes elusive goal. Research in physical-layer authentication using channel features holds promise as a technique to improve network security for a variety of devices. We propose the use of machine learning and measured multiple-input multiple-output communications channel information to make a decision on whether or not to authenticate a particular device. This work analyzes the use of received channel state information from the wireless environment and demonstrates the employment of a generative adversarial neural network (GAN) trained with received channel data to authenticate a transmitting device. We compared a variety of machine learning techniques and found that the local outlier factor (LOF) algorithm reached 100% accuracy at lower signal to noise ratios (SNR) than other algorithms. However, before LOF reached 100%, we also show that the GAN was more accurate at lower SNR levels.Comment: Submitted to 14th International Conference on Signal Processing and Communication Systems (ICSPCS) 202

DeepCSI: Rethinking Wi-Fi Radio Fingerprinting Through MU-MIMO CSI Feedback Deep Learning

We present DeepCSI, a novel approach to Wi-Fi radio fingerprinting (RFP) which leverages standard-compliant beamforming feedback matrices to authenticate MU-MIMO Wi-Fi devices on the move. By capturing unique imperfections in off-the-shelf radio circuitry, RFP techniques can identify wireless devices directly at the physical layer, allowing low-latency low-energy cryptography-free authentication. However, existing Wi-Fi RFP techniques are based on software-defined radio (SDRs), which may ultimately prevent their widespread adoption. Moreover, it is unclear whether existing strategies can work in the presence of MU-MIMO transmitters - a key technology in modern Wi-Fi standards. Conversely from prior work, DeepCSI does not require SDR technologies and can be run on any low-cost Wi-Fi device to authenticate MU-MIMO transmitters. Our key intuition is that imperfections in the transmitter's radio circuitry percolate onto the beamforming feedback matrix, and thus RFP can be performed without explicit channel state information (CSI) computation. DeepCSI is robust to inter-stream and inter-user interference being the beamforming feedback not affected by those phenomena. We extensively evaluate the performance of DeepCSI through a massive data collection campaign performed in the wild with off-the-shelf equipment, where 10 MU-MIMO Wi-Fi radios emit signals in different positions. Experimental results indicate that DeepCSI correctly identifies the transmitter with an accuracy of up to 98%. The identification accuracy remains above 82% when the device moves within the environment. To allow replicability and provide a performance benchmark, we pledge to share the 800 GB datasets - collected in static and, for the first time, dynamic conditions - and the code database with the community.Comment: To be presented at the 42nd IEEE International Conference on Distributed Computing Systems (ICDCS), Bologna, Italy, July 10-13, 202

Wireless Device Authentication Techniques Using Physical-Layer Device Fingerprint

Due to the open nature of the radio signal propagation medium, wireless communication is inherently more vulnerable to various attacks than wired communication. Consequently, communication security is always one of the critical concerns in wireless networks. Given that the sophisticated adversaries may cover up their malicious behaviors through impersonation of legitimate devices, reliable wireless authentication is becoming indispensable to prevent such impersonation-based attacks through verification of the claimed identities of wireless devices. Conventional wireless authentication is achieved above the physical layer using upper-layer identities and key-based cryptography. As a result, user authenticity can even be validated for the malicious attackers using compromised security key. Recently, many studies have proven that wireless devices can be authenticated by exploiting unique physical-layer characteristics. Compared to the key-based approach, the possession of such physical-layer characteristics is directly associated with the transceiver\u27s unique radio-frequency hardware and corresponding communication environment, which are extremely difficult to forge in practice. However, the reliability of physical-layer authentication is not always high enough. Due to the popularity of cooperative communications, effective implementation of physical-layer authentication in wireless relay systems is urgently needed. On the other hand, the integration with existing upper-layer authentication protocols still has many challenges, e.g., end-to-end authentication. This dissertation is motivated to develop novel physical-layer authentication techniques in addressing the aforementioned challenges. In achieving enhanced wireless authentication, we first specifically identify the technique challenges in authenticating cooperative amplify-and-forward (AF) relay. Since AF relay only works at the physical layer, all of the existing upper-layer authentication protocols are ineffective in identifying AF relay nodes. To solve this problem, a novel device fingerprint of AF relay consisting of wireless channel gains and in-phase and quadrature imbalances (IQI) is proposed. Using this device fingerprint, satisfactory authentication accuracy is achieved when the signal-to-noise ratio is high enough. Besides, the optimal AF relay identification system is studied to maximize the performance of identifying multiple AF relays in the low signal-to-noise regime and small IQI. The optimal signals for quadrature amplitude modulation and phase shift keying modulations are derived to defend against the repeated access attempts made by some attackers with specific IQIs. Exploring effective authentication enhancement technique is another key objective of this dissertation. Due to the fast variation of channel-based fingerprints as well as the limited range of device-specific fingerprints, the performance of physical-layer authentication is not always reliable. In light of this, the physical-layer authentication is enhanced in two aspects. On the one hand, the device fingerprinting can be strengthened by considering multiple characteristics. The proper characteristics selection strategy, measurement method and optimal weighted combination of the selected characteristics are investigated. On the other hand, the accuracy of fingerprint estimation and differentiation can be improved by exploiting diversity techniques. To be specific, cooperative diversity in the form of involving multiple collaborative receivers is used in differentiating both frequency-dependent and frequency-independent device fingerprints. As a typical combining method of the space diversity techniques, the maximal-ratio combining is also applied in the receiver side to combat the channel degeneration effect and increase the fingerprint-to-noise ratio. Given the inherent weaknesses of the widely utilized upper-layer authentication protocols, it is straightforward to consider physical-layer authentication as an effective complement to reinforce existing authentication schemes. To this end, a cross-layer authentication is designed to seamlessly integrate the physical-layer authentication with existing infrastructures and protocols. The specific problems such as physical-layer key generation as well as the end-to-end authentication in networks are investigated. In addition, the authentication complexity reduction is also studied. Through prediction, pre-sharing and reusing the physical-layer information, the authentication processing time can be significantly shortened

Stay Connected, Leave no Trace: Enhancing Security and Privacy in WiFi via Obfuscating Radiometric Fingerprints

The intrinsic hardware imperfection of WiFi chipsets manifests itself in the transmitted signal, leading to a unique radiometric fingerprint. This fingerprint can be used as an additional means of authentication to enhance security. In fact, recent works propose practical fingerprinting solutions that can be readily implemented in commercial-off-the-shelf devices. In this paper, we prove analytically and experimentally that these solutions are highly vulnerable to impersonation attacks. We also demonstrate that such a unique device-based signature can be abused to violate privacy by tracking the user device, and, as of today, users do not have any means to prevent such privacy attacks other than turning off the device. We propose RF-Veil, a radiometric fingerprinting solution that not only is robust against impersonation attacks but also protects user privacy by obfuscating the radiometric fingerprint of the transmitter for non-legitimate receivers. Specifically, we introduce a randomized pattern of phase errors to the transmitted signal such that only the intended receiver can extract the original fingerprint of the transmitter. In a series of experiments and analyses, we expose the vulnerability of adopting naive randomization to statistical attacks and introduce countermeasures. Finally, we show the efficacy of RF-Veil experimentally in protecting user privacy and enhancing security. More importantly, our proposed solution allows communicating with other devices, which do not employ RF-Veil.Comment: ACM Sigmetrics 2021 / In Proc. ACM Meas. Anal. Comput. Syst., Vol. 4, 3, Article 44 (December 2020