Dimensional reduction analysis for Physical Layer device fingerprints with application to ZigBee and Z-Wave devices

Radio Frequency RF Distinct Native Attribute (RF-DNA) Fingerprinting is a PHY-based security method that enhances device identification (ID). ZigBee 802.15.4 security is of interest here given its widespread deployment in Critical Infra-structure (CI) applications. RF-DNA features can be numerous, correlated, and noisy. Feature Dimensional Reduction Analysis (DRA) is considered here with a goal of: (1) selecting appropriate features (feature selection) and (2) selecting the appropriate number of features (dimensionality assessment). Five selection methods are considered based on Generalized Relevance Learning Vector Quantization-Improved (GRLVQI) feature relevance ranking, and p-value and test statistic rankings from both the two-sample Kolmogorov-Smirnov (KS) Test and the one-way Analysis of Variance (ANOVA) F-test. Dimensionality assessment is considered using previous qualitative (subjective) methods and quantitative methods developed herein using data covariance matrices and the KS and F-test p-values. ZigBee discrimination (classification and ID verification) is evaluated under varying signal-to-noise ratio (SNR) conditions for both authorized and unauthorized rogue devices. Test statistic approaches emerge as superior to p-value approaches and offer both higher resolution in selecting features and generally better device discrimination. With appropriate feature selection, using only 16% of the data is shown to achieve better classification performance than when using all of the data. Preliminary first-look results for Z-Wave devices are also presented and shown to be consistent with ZigBee device fingerprinting performance.