On Borrowed Time -- Preventing Static Power Side-Channel Analysis

In recent years, static power side-channel analysis attacks have emerged as a serious threat to cryptographic implementations, overcoming state-of-the-art countermeasures against side-channel attacks. The continued down-scaling of semiconductor process technology, which results in an increase of the relative weight of static power in the total power budget of circuits, will only improve the viability of static power side-channel analysis attacks. Yet, despite the threat posed, limited work has been invested into mitigating this class of attack. In this work we address this gap. We observe that static power side-channel analysis relies on stopping the target circuit's clock over a prolonged period, during which the circuit holds secret information in its registers. We propose Borrowed Time, a countermeasure that hinders an attacker's ability to leverage such clock control. Borrowed Time detects a stopped clock and triggers a reset that wipes any registers containing sensitive intermediates, whose leakages would otherwise be exploitable. We demonstrate the effectiveness of our countermeasure by performing practical Correlation Power Analysis attacks under optimal conditions against an AES implementation on an FPGA target with and without our countermeasure in place. In the unprotected case, we can recover the entire secret key using traces from 1,500 encryptions. Under the same conditions, the protected implementation successfully prevents key recovery even with traces from 1,000,000 encryptions

The Impostor Among US(B): Off-Path Injection Attacks on USB Communications

USB is the most prevalent peripheral interface in modern computer systems and its inherent insecurities make it an appealing attack vector. A well-known limitation of USB is that traffic is not encrypted. This allows on-path adversaries to trivially perform man-in-the-middle attacks. Off-path attacks that compromise the confidentiality of communications have also been shown to be possible. However, so far no off-path attacks that breach USB communications integrity have been demonstrated. In this work we show that the integrity of USB communications is not guaranteed even against off-path attackers.Specifically, we design and build malicious devices that, even when placed outside of the path between a victim device and the host, can inject data to that path. Using our developed injectors we can falsify the provenance of data input as interpreted by a host computer system. By injecting on behalf of trusted victim devices we can circumvent any software-based authorisation policy defences that computer systems employ against common USB attacks. We demonstrate two concrete attacks. The first injects keystrokes allowing an attacker to execute commands. The second demonstrates file-contents replacement including during system install from a USB disk. We test the attacks on 29 USB 2.0 and USB 3.x hubs and find 14 of them to be vulnerable.Comment: To appear in USENIX Security 202

Revealing the Appetite of the Marine Aquarium Fish Trade: The Volume and Biodiversity of Fish Imported into the United States

The aquarium trade and other wildlife consumers are at a crossroads forced by threats from global climate change and other anthropogenic stressors that have weakened coastal ecosystems. While the wildlife trade may put additional stress on coral reefs, it brings income into impoverished parts of the world and may stimulate interest in marine conservation. To better understand the influence of the trade, we must first be able to quantify coral reef fauna moving through it. Herein, we discuss the lack of a data system for monitoring the wildlife aquarium trade and analyze problems that arise when trying to monitor the trade using a system not specifically designed for this purpose. To do this, we examined an entire year of import records of marine tropical fish entering the United States in detail, and discuss the relationship between trade volume, biodiversity and introduction of non-native marine fishes. Our analyses showed that biodiversity levels are higher than previous estimates. Additionally, more than half of government importation forms have numerical or other reporting discrepancies resulting in the overestimation of trade volumes by 27%. While some commonly imported species have been introduced into the coastal waters of the USA (as expected), we also found that some uncommon species in the trade have also been introduced. This is the first study of aquarium trade imports to compare commercial invoices to government forms and provides a means to, routinely and in real time, examine the biodiversity of the trade in coral reef wildlife species

The Role of Turtles as Coral Reef Macroherbivores

Herbivory is widely accepted as a vital function on coral reefs. To date, the majority of studies examining herbivory in coral reef environments have focused on the roles of fishes and/or urchins, with relatively few studies considering the potential role of macroherbivores in reef processes. Here, we introduce evidence that highlights the potential role of marine turtles as herbivores on coral reefs. While conducting experimental habitat manipulations to assess the roles of herbivorous reef fishes we observed green turtles (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata) showing responses that were remarkably similar to those of herbivorous fishes. Reducing the sediment load of the epilithic algal matrix on a coral reef resulted in a forty-fold increase in grazing by green turtles. Hawksbill turtles were also observed to browse transplanted thalli of the macroalga Sargassum swartzii in a coral reef environment. These responses not only show strong parallels to herbivorous reef fishes, but also highlight that marine turtles actively, and intentionally, remove algae from coral reefs. When considering the size and potential historical abundance of marine turtles we suggest that these potentially valuable herbivores may have been lost from many coral reefs before their true importance was understood

Micro-combs: a novel generation of optical sources

The quest towards the integration of ultra-fast, high-precision optical clocks is reflected in the large number of high-impact papers on the topic published in the last few years. This interest has been catalysed by the impact that high-precision optical frequency combs (OFCs) have had on metrology and spectroscopy in the last decade [1–5]. OFCs are often referred to as optical rulers: their spectra consist of a precise sequence of discrete and equally-spaced spectral lines that represent precise marks in frequency. Their importance was recognised worldwide with the 2005 Nobel Prize being awarded to T.W. Hänsch and J. Hall for their breakthrough in OFC science [5]. They demonstrated that a coherent OFC source with a large spectrum – covering at least one octave – can be stabilised with a self-referenced approach, where the frequency and the phase do not vary and are completely determined by the source physical parameters. These fully stabilised OFCs solved the challenge of directly measuring optical frequencies and are now exploited as the most accurate time references available, ready to replace the current standard for time. Very recent advancements in the fabrication technology of optical micro-cavities [6] are contributing to the development of OFC sources. These efforts may open up the way to realise ultra-fast and stable optical clocks and pulsed sources with extremely high repetition-rates, in the form of compact and integrated devices. Indeed, the fabrication of high-quality factor (high-Q) micro-resonators, capable of dramatically amplifying the optical field, can be considered a photonics breakthrough that has boosted not only the scientific investigation of OFC sources [7–13] but also of optical sensors and compact light modulators [6,14]

Chemistry and medical implications of novel amphibian peptides : a thesis submitted for the degree of Doctor of Philosophy / by Paul Andrew Wabnitz.

Copies of author's previously published articles inserted.Includes bibliographical references.xv, 210 leaves : ill. ; 30 cm.A chemical and pharmacological investigation of compounds derived from amphibian skin. Isolates novel amphibian peptides and further investigates the biological activity of some of the peptides discovered.Thesis (Ph.D.)--University of Adelaide, Dept. of Chemistry, 200

A Spiking Neural Network Based Auto-encoder for Anomaly Detection in Streaming Data

Anomaly Detection (AD) is useful for a range of applications including cyber security, health analytics, robotics, defense and big data. Automating the detection of anomalies is necessary to deal with large volumes of data and to satisfy real time processing constraints. Current Machine Learning (ML) methods have had some success in the automated detection of anomalies, but no ideal ML solutions have been found for any domain. Spiking Neural Networks (SNNs), an emerging ML technique, have the potential to do AD well, especially for Edge applications where it needs to be low power, readily adaptable, autonomous and reliable. Here we investigate SNNs doing anomaly detection on streams of text. We show that SNNs are well suited for detecting anomalous character sequences, that they can learn rapidly, and that there are many optimizations to the SNN architecture and training that can improve AD performance.</p

Unsupervised Feature Vector Clustering Using Temporally Coded Spiking Networks

Spiking Neural Networks (SNNs) remain on the fringe of machine learning research despite their potential for fast low-power performance and fully local operation, including rapid online learning, on edge computing devices. In SNNs, encoding information in the timing of individual spikes is more efficient than using spiking rates for which many spikes are required. However, combining spike-time coding with unsupervised learning has proven somewhat challenging. Here we use spike latency coding with local unsupervised spike-timing-dependent plasticity and several biologically inspired local homeostatic mechanisms that maintain network stability. We show that when trained on sequences of characters from text, the network rapidly and effectively self-organizes to learn a latent space mapping of character attributes, similar to word2vec but for characters (i.e. char2vec), forming clusters of vowels, consonants and punctuation for example. It does so with no explicit objective function and no error signal, showing that time-encoded unsupervised SNNs (STUNNs) can maintain dynamical stability while self-organizing to extract complex input relationships using only local learning rules.</p

Time domain reconstruction of spatial sound fields using compressed sensing

A novel technique for time domain spatial sound reproduction using compressed sensing is presented. The presented technique is based on the application of compressed sensing theory, which is used to improve the accuracy of the reconstructed sound field. In addition, singular value decomposition is also applied, which acts to significantly reduce the size of the data set to process, thus making it efficient and realisable for real-time applications. Results are presented from the preliminary performance evaluation of the compressed sensing technique in comparison to the Higher Order Ambisonic reconstruction technique

Open platform, 32-channel, portable, data-logger with 32 PGA control lines for wearable medical device development

A compact isolated low-power 32-channel 16-bit data-logging system around an NXP ARM processor (LPC1768) and four of the linear technology octal analogue-to-digital converters (ADCs) LTC1857/58/59 is designed. The system requires only 250 mA when powered at 5 V to run at full power (including a capacitive 2.8 inch touch-screen display and 32 Gb SHDC SD memory card). The sample rate is configurable up to 1 k SPS per channel as well as voltage dynamic input up to ±10 V; additionally, 32 chip select lines (SPI protocol) individually addressable and controllable while sampling to configure userdesigned programmable gain amplifiers (PGAs) are available. Collaboration is being sought to improve the software capabilities, particularly to enrich the very basic user interface and to add wireless connectivity. The code is available (under the GPL licence) at our repository, the gerber file to reproduce the PCB is available (on the As-Is basis) on request. The galvanic isolation between the power supply data connection and ADC channels makes the data-logger also compatible with the main powered PCs, hence it is suitable for the implementation of medical devices at least for the prototyping and initial testing stages