Preserving Both Privacy and Utility in Network Trace Anonymization

As network security monitoring grows more sophisticated, there is an increasing need for outsourcing such tasks to third-party analysts. However, organizations are usually reluctant to share their network traces due to privacy concerns over sensitive information, e.g., network and system configuration, which may potentially be exploited for attacks. In cases where data owners are convinced to share their network traces, the data are typically subjected to certain anonymization techniques, e.g., CryptoPAn, which replaces real IP addresses with prefix-preserving pseudonyms. However, most such techniques either are vulnerable to adversaries with prior knowledge about some network flows in the traces, or require heavy data sanitization or perturbation, both of which may result in a significant loss of data utility. In this paper, we aim to preserve both privacy and utility through shifting the trade-off from between privacy and utility to between privacy and computational cost. The key idea is for the analysts to generate and analyze multiple anonymized views of the original network traces; those views are designed to be sufficiently indistinguishable even to adversaries armed with prior knowledge, which preserves the privacy, whereas one of the views will yield true analysis results privately retrieved by the data owner, which preserves the utility. We present the general approach and instantiate it based on CryptoPAn. We formally analyze the privacy of our solution and experimentally evaluate it using real network traces provided by a major ISP. The results show that our approach can significantly reduce the level of information leakage (e.g., less than 1\% of the information leaked by CryptoPAn) with comparable utility

System Level Assessment of Motor Control through Patterned Microstimulation in the Superior Colliculus

We are immersed in an environment full of sensory information, and without much thought or effort we can produce orienting responses to appropriately react to different stimuli. This seemingly simple and reflexive behavior is accomplished by a very complicated set of neural operations, in which motor systems in the brain must control behavior based on populations of sensory information. The oculomotor or saccadic system is particularly well studied in this regard. Within a visual environment consisting of many potential stimuli, we control our gaze with rapid eye movements, or saccades, in order to foveate visual targets of interest. A key sub-cortical structure involved in this process is the superior colliculus (SC). The SC is a structure in the midbrain which receives visual input and in turn projects to lower-level areas in the brainstem that produce saccades. Interestingly, microstimulation of the SC produces eye movements that match the metrics and kinematics of naturally-evoked saccades. As a result, we explore the role of the SC in saccadic motor control by manually introducing distributions of activity through neural stimulation. Systematic manipulation of microstimulation patterns were used to characterize how ensemble activity in the SC is decoded to generate eye movements. Specifically, we focused on three different facets of saccadic motor control. In the first study, we examine the effective influence of microstimulation parameters on behavior to reveal characteristics of the neural mechanisms underlying saccade generation. In the second study, we experimentally verify the predictions of computational algorithms that are used to describe neural mechanisms for saccade generation. And in the third study, we assess where neural mechanisms for decoding occur within the oculomotor network in order to establish the order of operations necessary for saccade generation. The experiments assess different aspects of saccadic motor control, which collectively, reveal properties and mechanisms that contribute to the comprehensive understanding of signal processing in the oculomotor system

Conceptual challenges for interpretable machine learning

As machine learning has gradually entered into ever more sectors of public and private life, there has been a growing demand for algorithmic explainability. How can we make the predictions of complex statistical models more intelligible to end users? A subdiscipline of computer science known as interpretable machine learning (IML) has emerged to address this urgent question. Numerous influential methods have been proposed, from local linear approximations to rule lists and counterfactuals. In this article, I highlight three conceptual challenges that are largely overlooked by authors in this area. I argue that the vast majority of IML algorithms are plagued by (1) ambiguity with respect to their true target; (2) a disregard for error rates and severe testing; and (3) an emphasis on product over process. Each point is developed at length, drawing on relevant debates in epistemology and philosophy of science. Examples and counterexamples from IML are considered, demonstrating how failure to acknowledge these problems can result in counterintuitive and potentially misleading explanations. Without greater care for the conceptual foundations of IML, future work in this area is doomed to repeat the same mistakes

Digital Marketing and the Culture Industry: The Ethics of Big Data

Instead of the steady march of the one percent growth in ecommerce as compared to total retail revenues in the last decade (to comprise about nine percent of the industry at the close of 2019), we have witnessed leaps now to over twenty percent in just the last year. Scott Galloway marks the pandemic as an accelerant not just of digital marketing posting a year of growth for each month of quarantine but as an accelerant of each major GAFA (Google, Amazon, Facebook, and Apple) firm from market dominance to total dominance (Galloway 2020). Viewing these trends from the standpoint of critical marketing requires revisiting first-generation critical theorist reflections on the American dominance of the global culture industry. Insofar as GAFA digital marketing practices highlight their transition from mere neutral platforms to shapers, creators, and drivers of cultural content, we need to complement marketing’s praiseworthy achievements in statistical modeling (like SEM) with a sufficiently critical and theoretical contextualization. In this sense, while my investigation of big data will certainly countenance and explore its statistical (as algorithmic) innovations, what I capitalize as Big Data connotes the manners in which these large reserves of behavioral exhaust shape culture—domestic and global, home and workplace, private and public. The focus on ethics in each of these three articles follows not just moral norms, social practices, and associated virtues (or vices), but also the important ethical domains of compliance, basic rights, and juridical precedent. In the first article, I focus most exclusively on the manners in which GAFA algorithmic personalization tends to employ the alluring promise of individual tailoring of service convenience at the social costs of echo chambers, filter bubbles, and endemic political polarization. In the second article, I seek to devise a data theory of value as the wider context for my proposal to advance a new marketing mix. My tentative argument is that the classical subject as constructed by these platform domains has now juxtaposed the consumer and firm relationship. The true value creators of the workforce of the digital marketplace are its users as prosumers: an odd mixture of consumer, producer, and product. While the production era took nature as the collateral damage to its claims upon mining limited raw materials, the onset of a consumption driven economy harvests psychic and behavioral data as its new unlimited raw material with its own trails of collateral damage that constitute the birth of surveillance capitalism (Zuboff 2019). In the third article, I turn to systemic racism in American sport with the focus on the performative rituals sanctioned, censored, and sold by the NFL as its foremost culture industry. In this last article, I also seek to develop a revamped epistemology for critical marketing that places a new primacy on the voices and experiences of those most systemically marginalized as the best lens from which to advance theories and practices that can disclose forms of latent domination often hidden behind otherwise an uncritical acceptance of the NFL culture industry as fundamentally apolitical leisurely entertainment

Miniscope in vivo imaging of neuronal ensembles in the central amygdala in mice

Advancements in both calcium indicators and optical instrumentation have led to new in vivo techniques, such as Miniscopes, capable of recording the spatiotemporal activity of multiple neurons during unrestrained behaviour in rodents. With these microendoscopic techniques, neuronal populations can be stably recorded over multiple sessions. As a result, Miniscopes allow for the investigation of a brain region’s changing activity patterns as a result of disease progression or behaviour. Recently, open source Miniscope initiatives have led to affordable and accessible versions of this technique. In addition, the collaborative open-source community facilitates rapidly evolving modifications, implementations and designs. Notwithstanding the potential and ever-increasing popularity of Miniscopes, the technique is still in its infancy and not widespread. This study consisted of a background review and a pilot study attempting to image neuronal ensembles in the central nucleus of the amygdala (CeA) using the open-source UCLA V3 Miniscope in mice. Despite not being able to successfully record neuronal activity in the CeA, the study has made progress in generating a protocol for Miniscope implementation at the Pharmacology department of Helsinki. Moreover, the study proposes different adjustments that might be implemented in the future. With the continuation of a synergistic collaboration with the Department of Psychology at the university of Jyväskylä, it is likely that both departments will be able to effectively implement the Miniscope technique in the foreseeable future

Hardware-Assisted Secure Computation

The theory community has worked on Secure Multiparty Computation (SMC) for more than two decades, and has produced many protocols for many settings. One common thread in these works is that the protocols cannot use a Trusted Third Party (TTP), even though this is conceptually the simplest and most general solution. Thus, current protocols involve only the direct players---we call such protocols self-reliant. They often use blinded boolean circuits, which has several sources of overhead, some due to the circuit representation and some due to the blinding. However, secure coprocessors like the IBM 4758 have actual security properties similar to ideal TTPs. They also have little RAM and a slow CPU.We call such devices Tiny TTPs. The availability of real tiny TTPs opens the door for a different approach to SMC problems. One major challenge with this approach is how to execute large programs on large inputs using the small protected memory of a tiny TTP, while preserving the trust properties that an ideal TTP provides. In this thesis we have investigated the use of real TTPs to help with the solution of SMC problems. We start with the use of such TTPs to solve the Private Information Retrieval (PIR) problem, which is one important instance of SMC. Our implementation utilizes a 4758. The rest of the thesis is targeted at general SMC. Our SMC system, Faerieplay, moves some functionality into a tiny TTP, and thus avoids the blinded circuit overhead. Faerieplay consists of a compiler from high-level code to an arithmetic circuit with special gates for efficient indirect array access, and a virtual machine to execute this circuit on a tiny TTP while maintaining the typical SMC trust properties. We report on Faerieplay\u27s security properties, the specification of its components, and our implementation and experiments. These include comparisons with the Fairplay circuit-based two-party system, and an implementation of the Dijkstra graph shortest path algorithm. We also provide an implementation of an oblivious RAM which supports similar tiny TTP-based SMC functionality but using a standard RAM program. Performance comparisons show Faerieplay\u27s circuit approach to be considerably faster, at the expense of a more constrained programming environment when targeting a circuit

Trophic Ecology and Mercury Concentrations of Canary Rockfish (Sebastes Pinniger) in the California Current System

Canary rockfish are a profitable fishery resource that has failed and successfully recovered in the 21st century. This study aimed to evaluate their trophic ecology through stomach content and stable isotope analysis and relate these to their mercury concentrations, biological traits, and environmental conditions. Canary rockfish consume mostly krill and teleosts with their geographic location affecting the proportion of prey items, suggesting regional environmental effects: chlorophyll-a, relief, port, and depth impact dietary choices. Mean ??13C values (-17.18 ± 0.54) significantly increased in individuals residing in deeper depths, higher latitudes, higher productivity, and higher temperatures, and in sexually mature individuals. Mean ??15N values (15.26 ± 0.63) increased in individuals within higher latitudes, hotter temperatures, and elevated productivity. Mean calculated trophic level (3.52 ± 0.64) significantly increased in larger individuals, and those residing in more complex and cooler environments. Total mercury concentrations (0.04-0.50 ppm) significantly increased with ontogenetic development, weight, Fulton’s K, and latitude. Individuals that consumed higher proportions of teleosts and were larger, sexually mature, and resided in productive, nearshore, or northern environments possessed higher mercury concentrations. Future research should explore if resource allocation changes throughout the year for Canary rockfish, and if mercury concentrations do pose a threat to regional commercial and recreational fisheries

Depth as refuge: depth gradients in ecological pattern, process, and risk mitigation among coral reef fishes

The impacts of anthropogenic habitat disturbance are often asymmetric along environmental gradients and among taxa. For species that cannot successfully utilize post disturbance habitats, the ability to occupy positions on spatial gradients that fall outside of disturbance regimes may offer a key refuge. However, decreasing resource availability or quality, and changing ecological and behavioural dynamics along gradients may result in substantial physiological costs for fringe-dwelling organisms. Assessments of potential refuges therefore require nuanced spatially gradated ecological assessments that are often absent and difficult to attain. Coral reefs are now heavily impacted by climate related disturbance, and the greatest rates of biotic attrition among reef fishes generally occur within species obligated to associate with live corals. Because key drivers of future coral loss (i.e. warm water bleaching and storm events) may attenuate with depth, deep reefs hypothetically offer a refuge to vulnerable fishes. However, because of access difficulties, most ecological studies on coral reef organisms occur in shallow waters of <15 m. In Chapter 2, I investigated the natural depth distributions, depth-related variation in community structure and coral habitat associations for 123 reef fish species at 6 depths between 0m and 40m, and from inner-bay to offshore reefs. The results indicated that depth is a stronger driver of reef fish assemblages than cross shelf gradients, though complex coral habitats and some associated fish species more frequently occupy deeper depths further from shore. Total live hard coral cover did not decline with depth in Kimbe Bay, though the cover of habitat-providing complex corals declined with depth. The major break in the community assemblage of reef fishes occurred between 5 m and 10 m, and 25% of species were limited to the shallowest 5m. However, 25% of species occurred at all depths between 0m and 30m, and 12% between 0m and 40m. In addition, I show that 85% of species with strong associations with live complex coral habitats occurred at depths of 20m or below. I therefore conclude that deep reef habitats in Kimbe Bay can provide a substantial refuge potential if reef degradation does attenuate with depth and the ecological costs of occupying deep periphery habitats are not prohibitive to long-term population maintenance. In Chapters 3 to 6, I utilized the Chaetodontidae family (Butterflyfishes) to further investigate how a broad suit of behaviours and ecological dynamics that influence the distribution, vulnerability and success of a wide range of taxa in multiple biomes interrelate and vary among reef fishes along a broad coral reef depth gradient, from 0 – 40 m. Interrelationships among distribution breadth, abundance, and degree of resource specialization form the basis of many general models in ecology, as well as extinction-risk assessments in conservation biology. Species with narrow distributions, low abundance and high resource specialisation are more vulnerable to environmental change and risk increases when vulnerability traits are combined. In Chapter 3, I evaluate whether depth may mediate these risks in coral-specialist fishes. Contrary to expectation, the most coral-specialized species were also the most abundant and the most broadly distributed. Further, no specialist-species had combined vulnerability traits, and no specialists were wholly restricted to shallow-water. Chapter 3 demonstrates that interrelationships among vulnerability traits and occupancy depths do not necessarily follow traditional ecological expectations on coral reefs, but they do work to mediate substantial risks for species vulnerable to shallow-reef habitat declines. Chapters 2 and 3 demonstrate that many ecologically vulnerable reef fish species may offset the risks associated with shallow-water habitat losses by utilising deep habitats. However, the refuge potential of deep peripheral habitats may be mediated by the potentially substantial costs of securing sparsely distributed resources, which can limit survival and reproductive output. Further, depth-related resource shifts are likely to be more detrimental to dietary specialists than to generalists. In Chapter 4, I use extensive and intensive in-situ behavioural observations in combination with physiological condition measurements to examine the costs and benefits of resource-acquisition along the depth-gradient in two obligate corallivore reef fishes with contrasting levels of dietary specialisiation. I demonstrate that the space utilised to secure coral-resources increases towards deeper depths, as expected. However, increased territory sizes result in equal or greater total resources secured within deep territories. Foraging-distance, pairing-behaviour, body condition and fecundity did not decline with depth, but competitive interactions did. Unexpectedly, therefore, coral-specialist fishes selecting high-quality coral patches in deep water access equal or greater resources than their shallow-reef counterparts, with no extra costs. As demonstrated in Chapter 4, the capacity for species to successfully occupy range peripheries is enhanced by their ability to mediate costs related to decreases in quantities and quality of key resources. In Chapter 5, I investigate the capacity to of species to employ variation in dietary strategies and energy acquisition along depth gradients. I focus on two obligate corallivores with differing levels of dietary specialization, as well as their mixotrophic coral prey. Total resource availability and total feeding effort did not decline toward deep-range peripheries in either fish species, but availability of preferred Acropora resources did decline. The more specialized species exhibited limited feeding plasticity along the depth gradient, and selective feeding effort on the preferred coral genus Acropora increased rather than decreased with depth. In contrast, the generalist's diet varied greatly with depth, reflecting changes in prey composition. Unexpectedly, the nutritional content of Acropora did not decline with depth, with shifts in δ¹³C and δ¹⁵N indicating increased coral heterotrophy in deeper water may offset declines in light energy. Mixed modelling of stable isotopes in amino acids of fish muscle tissue revealed a parallel increase in plankton-sourced carbon among deep-resident fish. Therefore, deep ranges appear to be supported by multiple mechanisms of dietary versatility, but for specialist species this versatility occurred at the resource level (corals), rather than among the consumers (fish). This dietary variability and trophic plasticity may act to buffer costs and bolster refuge potentials associated with dwelling at deep range peripheries, even among taxa with differential functional strategies. In Chapter 6, I utilize two natural experiments to 1) demonstrate that a natural habitat disturbance event (a crown of thorns sea-star outbreak) can result in differential impacts and outcomes on shallow and deep populations of the coral obligate reef fish Chaetodon baronessa that favour the persistence of deep population; and 2) individual fishes are able to migrate downward, away from territories in degrading shallow-water habitats to inhabit healthy deep-reef habitats when made available via experimental competitor removal. Overall, my thesis highlights how interrelationships among vulnerability traits, occupancy depths, and deep coral habitats, offer some risk mitigation among taxa currently thought to express high vulnerability to global-scale coral declines in shallow-water. The thesis further demonstrates how various combinations of stability and plasticity in resource specialization, space use, effort, food availability and quality, diet, feeding behaviour, and body condition, may aid the successful exploitation of deep refuges by species with contrasting functional traits. Finally, severe habitat disturbance can differentially impact fish and habitat survival between shallow and deep reefs, and individual fish are demonstrably able to utilize downward vertical migration away from declining shallow-water habitat to access higher-quality deep-water habitats where prior residence is not established

A Low-Randomness Second-Order Masked AES

We propose a second-order masking of the AES in hardware that requires an order of magnitude less random bits per encryption compared to previous work. The design and its security analysis are based on recent results by Beyne et al. from Asiacrypt 2020. Applying these results to the AES required overcoming significant engineering challenges by introducing new design techniques. Since the security analysis is based on linear cryptanalysis, the masked cipher needs to have sufficient diffusion and the S-box sharing must be highly nonlinear. Hence, in order to apply the changing of the guards technique, a detailed study of its effect on the diffusion of the linear layer becomes important. The security analysis is automated using an SMT solver. Furthermore, we propose a sharpening of the glitch-extended probing model that results in improvements to our concrete security bounds. Finally, it is shown how to amortize randomness costs over multiple evaluations of the masked cipher