Using RF-DNA Fingerprints to Discriminate ZigBee Devices in an Operational Environment

This research was performed to expand AFIT\u27s Radio Frequency Distinct Native Attribute (RF-DNA) fingerprinting process to support IEEE 802.15.4 ZigBee communication network applications. Current ZigBee bit-level security measures include use of network keys and MAC lists which can be subverted through interception and spoofing using open-source hacking tools. This work addresses device discrimination using Physical (PHY) waveform alternatives to augment existing bit-level security mechanisms. ZigBee network vulnerability to outsider threats was assessed using Receiver Operating Characteristic (ROC) curves to characterize both Authorized Device ID Verification performance (granting network access to authorized users presenting true bit-level credentials) and Rogue Device Rejection performance (denying network access to unauthorized rogue devices presenting false bit-level credentials). Radio Frequency Distinct Native Attribute (RF-DNA) features are extracted from time-domain waveform responses of 2.4 GHz CC2420 ZigBee transceivers to enable humanlike device discrimination. The fingerprints were constructed using a hybrid pool of emissions collected under a range of conditions, including anechoic chamber and an indoor office environment where dynamic multi-path and signal degradation factors were present. The RF-DNA fingerprints were input to a Multiple Discriminant Analysis, Maximum Likelihood (MDA/ML) discrimination process and a 1 vs. many Looks most like? classification assessment made. The hybrid MDA model was also used for 1 vs. 1 Looks how much like? verification assessment. ZigBee Device Classification performance was assessed using both full and reduced dimensional fingerprint sets. Reduced dimensional subsets were selected using Dimensional Reduction Analysis (DRA) by rank ordering 1) pre-classification KS-Test p-values and 2) post-classification GRLVQI feature relevance values. Assessment of Zigbee device ID verification capability

Absence of single-locus complementary sex determination in the braconid wasps Asobara tabida and Alysia manducator

In species with single-locus complementary sex determination (sl-CSD), sex is determined by multiple alleles at a single locus. In the haplodiploid Hymenoptera, sl-CSD results in females, if individuals are heterozygous at the sex locus, and in males, if individuals are hemizygous (haploid males) or homozygous (diploid males). Several hymenopteran species have been shown to have sl-CSD, but in several others sl-CSD is absent and the phylogenetic distribution remains unclear. In the family Braconidae, all four species tested so far were shown to possess sl-CSD. In this study, inbreeding experiments were used to test for the presence of sl-CSD in two species belonging to a subfamily of the Braconidae, Asobara tabida and Alysia manducator (Alysiinae). In both species inbreeding experiments showed no difference in brood size or sex ratio compared to the (outbred) control group. Furthermore, the sex ratios found in the inbreeding treatment differed significantly from the sex ratios expected under sl-CSD. Therefore, we conclude that sl-CSD is absent in these species. This study is the first to show the lack of sl-CSD in species of the Braconidae family and that hymenopteran sex-determining mechanisms can vary, even within a family.

Alternative patterns of sex chromosome differentiation in Aedes aegypti (L).

BACKGROUND: Some populations of West African Aedes aegypti, the dengue and zika vector, are reproductively incompatible; our earlier study showed that divergence and rearrangements of genes on chromosome 1, which bears the sex locus (M), may be involved. We also previously described a proposed cryptic subspecies SenAae (PK10, Senegal) that had many more high inter-sex FST genes on chromosome 1 than did Ae.aegypti aegypti (Aaa, Pai Lom, Thailand). The current work more thoroughly explores the significance of those findings. RESULTS: Intersex standardized variance (FST) of single nucleotide polymorphisms (SNPs) was characterized from genomic exome capture libraries of both sexes in representative natural populations of Aaa and SenAae. Our goal was to identify SNPs that varied in frequency between males and females, and most were expected to occur on chromosome 1. Use of the assembled AaegL4 reference alleviated the previous problem of unmapped genes. Because the M locus gene nix was not captured and not present in AaegL4, the male-determining locus, per se, was not explored. Sex-associated genes were those with FST values ≥ 0.100 and/or with increased expected heterozygosity (H exp , one-sided T-test, p < 0.05) in males. There were 85 genes common to both collections with high inter-sex FST values; all genes but one were located on chromosome 1. Aaa showed the expected cluster of high inter-sex FST genes proximal to the M locus, whereas SenAae had inter-sex FST genes along the length of chromosome 1. In addition, the Aaa M-locus proximal region showed increased H exp levels in males, whereas SenAae did not. In SenAae, chromosomal rearrangements and subsequent suppressed recombination may have accelerated X-Y differentiation. CONCLUSIONS: The evidence presented here is consistent with differential evolution of proto-Y chromosomes in Aaa and SenAae

ZigBee Device Verification for Securing Industrial Control and Building Automation Systems

Improved wireless ZigBee network security provides a means to mitigate malicious network activity due to unauthorized devices. Security enhancement using RF-based features can augment conventional bit-level security approaches that are solely based on the MAC addresses of ZigBee devices. This paper presents a device identity verification process using RF fingerprints from like-model CC2420 2.4 GHz ZigBee device transmissions in operational indoor scenarios involving line-of-sight and through-wall propagation channels, as well as an anechoic chamber representing near-ideal conditions. A trained multiple discriminant analysis model was generated using normalized multivariate Gaussian test statistics from authorized network devices. Authorized device classification and ID verification were assessed using pre-classification Kolmogorov-Smirnov (KS) feature ranking and post-classification generalized relevance learning vector quantization improved (GRLVQI) relevance ranking. A true verification rate greater than 90% and a false verification rate less than 10% were obtained when assessing authorized device IDs. When additional rogue devices were introduced that attempted to gain unauthorized network access by spoofing the bit-level credentials of authorized devices, the KS-test feature set achieved a true verification rate greater than 90% and a rogue reject rate greater than 90% in 29 of 36 rogue scenarios while the GRLVQI feature set was successful in 28 of 36 scenarios. Abstract © Springe

ZigBee Device Verification for Securing Industrial Control and Building Automation Systems

Improved wireless ZigBee network security provides a means to mitigate malicious network activity due to unauthorized devices. Security enhancement using RF-based features can augment conventional bit-level security approaches that are solely based on the MAC addresses of ZigBee devices. This paper presents a device identity verification process using RF fingerprints from like-model CC2420 2.4 GHz ZigBee device transmissions in operational indoor scenarios involving line-of-sight and through-wall propagation channels, as well as an anechoic chamber representing near-ideal conditions. A trained multiple discriminant analysis model was generated using normalized multivariate Gaussian test statistics from authorized network devices. Authorized device classification and ID verification were assessed using pre-classification Kolmogorov-Smirnov (KS) feature ranking and post-classification generalized relevance learning vector quantization improved (GRLVQI) relevance ranking. A true verification rate greater than 90% and a false verification rate less than 10% were obtained when assessing authorized device IDs. When additional rogue devices were introduced that attempted to gain unauthorized network access by spoofing the bit-level credentials of authorized devices, the KS-test feature set achieved a true verification rate greater than 90% and a rogue reject rate greater than 90% in 29 of 36 rogue scenarios while the GRLVQI feature set was successful in 28 of 36 scenarios. Abstract © Springe

The transformer2 gene in Musca domestica is required for selecting and maintaining the female pathway of development.

We present the isolation and functional analysis of a transformer2 homologue Mdtra2 in the housefly Musca domestica. Compromising the activity of this gene by injecting dsRNA into embryos causes complete sex reversal of genotypically female individuals into fertile males, revealing an essential function of Mdtra2 in female development of the housefly. Mdtra2 is required for female-specific splicing of Musca doublesex (Mddsx) which structurally and functionally corresponds to Drosophila dsx, the bottom-most regulator in the sex-determining pathway. Since Mdtra2 is expressed in males and females, we propose that Mdtra2 serves as an essential co-factor of F, the key sex-determining switch upstream of Mddsx. We also provide evidence that Mdtra2 acts upstream as a positive regulator of F supporting genetic data which suggest that F relies on an autocatalytic activity to select and maintain the female path of development. We further show that repression of male courtship behavior by F requires Mdtra2. This function of F and Mdtra2 appears not to be mediated by Mddsx, suggesting that bifurcation of the pathway at this level is a conserved feature in the genetic architecture of Musca and Drosophila