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David Barrera

Publications and source records attributed to David Barrera.

At least 19 recordsLinked to original sources

SoK: Is Sustainable the New Usable? Debunking The Myth of Fundamental Incompatibility Between Security and Sustainability

Every year, millions of functional systems become e-waste because users are pressured to send their systems to landfills due to a lack of vendor support and difficulty in recycling. Vendors cite ``cybersecurity'' as the driver for short product support periods, leading to a prevalent, but uninterrogated, belief that cybersecurity and environmental sustainability are fundamentally contradictory; i.e., it is difficult, if not impossible, to build products that are secure, long-lasting, and reusable. To understand the nuanced relationship between security and sustainability, we systematically analyze 29 papers and distill 155 sustainability guidelines into 12 sustainability themes. These themes enable us to compare the sustainable HCI and sustainable software engineering guidance with that of cybersecurity, identifying points of alignment and tension. We find little evidence of a fundamental tension between these two domains; the few instances of tension can be mitigated through thoughtful consideration of security and sustainability objectives. We also find that sustainability, like usable security, struggles with the myth of users as the weakest link and the individualization of responsibility. Building on these parallels, we argue that the usable security community is well-positioned to integrate sustainability considerations, as both fields share challenges in shifting responsibility from individuals to systemic design.

cs.HC

A Close Look at a Systematic Method for Analyzing Sets of Security Advice

We carry out a detailed analysis of the security advice coding method (SAcoding) of Barrera et al. (2021), which is designed to analyze security advice in the sense of measuring actionability and categorizing advice items as practices, policies, principles, or outcomes. The main part of our analysis explores the extent to which a second coder's assignment of codes to advice items agrees with that of a first, for a dataset of 1013 security advice items nominally addressing Internet of Things devices. More broadly, we seek a deeper understanding of the soundness and utility of the SAcoding method, and the degree to which it meets the design goal of reducing subjectivity in assigning codes to security advice items. Our analysis results in suggestions for modifications to the coding tree methodology, and some recommendations. We believe the coding tree approach may be of interest for analysis of qualitative data beyond security advice datasets alone.

cs.CR

Towards Characterizing IoT Software Update Practices

Software updates are critical for ensuring systems remain free of bugs and vulnerabilities while they are in service. While many Internet of Things (IoT) devices are capable of outlasting desktops and mobile phones, their software update practices are not yet well understood, despite a large body of research aiming to create new methodologies for keeping IoT devices up to date. This paper discusses efforts towards characterizing the IoT software update landscape through network-level analysis of IoT device traffic. Our results suggest that vendors do not currently follow security best practices, and that software update standards, while available, are not being deployed.

cs.CR

Security Best Practices: A Critical Analysis Using IoT as a Case Study

Academic research has highlighted the failure of many Internet of Things (IoT) product manufacturers to follow accepted practices, while IoT security best practices have recently attracted considerable attention worldwide from industry and governments. Given current examples of security advice, confusion is evident from guidelines that conflate desired outcomes with security practices to achieve those outcomes. We explore a surprising lack of clarity, and void in the literature, on what (generically) best practice means, independent of identifying specific individual practices or highlighting failure to follow best practices. We consider categories of security advice, and analyze how they apply over the lifecycle of IoT devices. For concreteness in discussion, we use iterative inductive coding to code and systematically analyze a set of 1013 IoT security best practices, recommendations, and guidelines collated from industrial, government, and academic sources. Among our findings, of all analyzed items, 68% fail to meet our definition of an (actionable) practice, and 73% of all actionable advice relates to the software development lifecycle phase, highlighting the critical position of manufacturers and developers. We hope that our work provides a basis for the community to better understand best practices, identify and reach consensus on specific practices, and find ways to motivate relevant stakeholders to follow them.

cs.CR

Ontology-Based Anomaly Detection for Air Traffic Control Systems

The Automatic Dependent Surveillance-Broadcast (ADS-B) protocol is increasingly being adopted by the aviation industry as a method for aircraft to relay their position to Air Traffic Control (ATC) monitoring systems. ADS-B provides greater precision compared to traditional radar-based technologies, however, it was designed without any encryption or authentication mechanisms and has been shown to be susceptible to spoofing attacks. A capable attacker can transmit falsified ADS-B messages with the intent of causing false information to be shown on ATC displays and threaten the safety of air traffic. Updating the ADS-B protocol will be a lengthy process, therefore, there is a need for systems to detect anomalous ADS-B communications. This paper presents ATC-Sense, an ADS-B anomaly detection system based on ontologies. An ATC ontology is used to model entities in a simulated controlled airspace and is used to detect falsified ADS-B messages by verifying that the entities conform to aviation constraints related to aircraft flight tracks, radar readings, and flight reports. We evaluate the computational performance of the proposed constraints-based detection approach with several ADS-B attack scenarios in a simulated ATC environment. We demonstrate how ontologies can be used for anomaly detection in a real-time environment and call for future work to investigate ways to improve the computational performance of such an approach.

cs.CR

Confidence intervals for nonparametric regression

We demonstrate and discuss nonasymptotic bounds in probability for the cost of a regression scheme with a general loss function from the perspective of the Rademacher theory, and for the optimality with respect to the average $L^{2}$-distance to the underlying conditional expectations of least squares regression outcomes from the perspective of the Vapnik-Chervonenkis theory. The results follow from an analysis involving independent but possibly nonstationary training samples and can be extended, in a manner that we explain and illustrate, to relevant cases in which the training sample exhibits dependence.

math.ST

Generalization bounds for nonparametric regression with $β-$mixing samples

In this paper we present a series of results that permit to extend in a direct manner uniform deviation inequalities of the empirical process from the independent to the dependent case characterizing the additional error in terms of $β-$mixing coefficients associated to the training sample. We then apply these results to some previously obtained inequalities for independent samples associated to the deviation of the least-squared error in nonparametric regression to derive corresponding generalization bounds for regression schemes in which the training sample may not be independent. These results provide a framework to analyze the error associated to regression schemes whose training sample comes from a large class of $β-$mixing sequences, including geometrically ergodic Markov samples, using only the independent case. More generally, they permit a meaningful extension of the Vapnik-Chervonenkis and similar theories for independent training samples to this class of $β-$mixing samples.

math.ST

BPFContain: Fixing the Soft Underbelly of Container Security

Linux containers currently provide limited isolation guarantees. While containers separate namespaces and partition resources, the patchwork of mechanisms used to ensure separation cannot guarantee consistent security semantics. Even worse, attempts to ensure complete coverage results in a mishmash of policies that are difficult to understand or audit. Here we present BPFContain, a new container confinement mechanism designed to integrate with existing container management systems. BPFContain combines a simple yet flexible policy language with an eBPF-based implementation that allows for deployment on virtually any Linux system running a recent kernel. In this paper, we present BPFContain's policy language, describe its current implementation as integrated into docker, and present benchmarks comparing it with current container confinement technologies.

cs.CR

Opto-Mechanical Interactions in Multi-Core Optical Fibers and Their Applications

Optical fibers containing multiple cores are being developed towards capacity enhancement in space-division multiplexed optical communication networks. In many cases, the fibers are designed for negligible direct coupling of optical power among the cores. The cores remain, however, embedded in a single, mechanically-unified cladding. Elastic (or acoustic) modes supported by the fiber cladding geometry are in overlap with multiple cores. Acoustic waves may be stimulated by light in any core through electrostriction. Once excited, the acoustic waves may induce photo-elastic perturbations to optical waves in other cores as well. Such opto-mechanical coupling gives rise to inter-core cross-phase modulation effects, even when direct optical crosstalk is very weak. The cross-phase modulation spectrum reaches hundreds of megahertz frequencies. It may consist of discrete and narrow peaks, or may become quasi-continuous, depending on the geometric layout. The magnitude of the effect at the resonance frequencies is comparable with that of intra-core cross-phase modulation due to Kerr nonlinearity. Two potential applications are demonstrated: single-frequency opto-electronic oscillators that do not require radio-frequency electrical filters, and point-sensing of liquids outside the cladding of multi-core fibers, where light cannot reach.

physics.app-ph

SERENIoT: Collaborative Network Security Policy Management and Enforcement for Smart Homes

Network traffic whitelisting has emerged as a dominant approach for securing consumer IoT devices. However, determining what the whitelisted behavior of an IoT device should be remains an open challenge. Proposals to date have relied on manufacturers and trusted parties to provide whitelists, but these proposals require manufacturer involvement or placing trust in an additional stakeholder. Alternatively, locally monitoring devices can allow building whitelists of observed behavior, but devices may not exhaust their functionality set during the observation period, or the behavior may change following a software update which requires re-training. This paper proposes a blockchain-based system for determining whether an IoT device is behaving like other devices of the same type. Our system (SERENIoT, pronounced Serenity) overcomes the challenge of initially determining the correct behavior for a device. Nodes in the SERENIoT public blockchain submit summaries of the network behavior observed for connected IoT devices and build whitelists of behavior observed by the majority of nodes. Changes in behavior through software updates are automatically whitelisted once the update is broadly deployed. Through a proof-of-concept implementation of SERENIoT on a small Raspberry Pi IoT network and a large-scale Amazon EC2 simulation, we evaluate the security, scalability, and performance of our system.

cs.CR

Space-division multiplexing for fiber-wireless communications

We envision the application of optical Space-division Multiplexing (SDM) to the next generation fiber-wireless communications as a firm candidate to increase the end user capacity and provide adaptive radiofrequency-photonic interfaces. This approach relies on the concept of fiber-distributed signal processing, where the SDM fiber provides not only radio access distribution but also broadband microwave photonics signal processing. In particular, we present two different SDM fiber technologies: dispersion-engineered heterogeneous multicore fiber links and multicavity devices built upon the selective inscription of gratings in homogeneous multicore fibers.

eess.SP

TARANET: Traffic-Analysis Resistant Anonymity at the NETwork layer

Modern low-latency anonymity systems, no matter whether constructed as an overlay or implemented at the network layer, offer limited security guarantees against traffic analysis. On the other hand, high-latency anonymity systems offer strong security guarantees at the cost of computational overhead and long delays, which are excessive for interactive applications. We propose TARANET, an anonymity system that implements protection against traffic analysis at the network layer, and limits the incurred latency and overhead. In TARANET's setup phase, traffic analysis is thwarted by mixing. In the data transmission phase, end hosts and ASes coordinate to shape traffic into constant-rate transmission using packet splitting. Our prototype implementation shows that TARANET can forward anonymous traffic at over 50~Gbps using commodity hardware.

cs.CR

Quenched Invariance Principles for the Discrete Fourier Transforms of a Stationary Process

In this paper, we study the asymptotic behavior of the normalized cadlag functions generated by the discrete Fourier transforms of a stationary centered square-integrable process, started at a point. We prove that the quenched invariance principle holds for averaged frequencies under no assumption other than ergodicity, and that this result holds also for almost every fixed frequency under a certain generalization of the Hannan condition and a certain rotated form of the Maxwell and Woodroofe condition which, under a condition of weak dependence that we specify, is guaranteed for a.e. frequency. If the process is in particular weakly mixing, our results describe the asymptotic distributions of the normalized discrete Fourier transforms at every frequency other than $0$ and $π$ under the generalized Hannan condition. We prove also that under a certain regularity hypothesis the conditional centering is irrelevant for averaged frequencies, and that the same holds for a given fixed frequency under the rotated Maxwell and Woodroofe condition but not necessarily under the generalized Hannan condition. In particular, this implies that the hypothesis of regularity is not sufficient for functional convergence without random centering at a.e. fixed frequency. The proofs are based on martingale approximations and combine results from Ergodic theory of recent and classical origin with approximation results by contemporary authors and with some facts from Harmonic Analysis and Functional Analysis.

math.PR

A first look at the usability of bitcoin key management

Bitcoin users are directly or indirectly forced to deal with public key cryptography, which has a number of security and usability challenges that differ from the password-based authentication underlying most online banking services. Users must ensure that keys are simultaneously accessible, resistant to digital theft and resilient to loss. In this paper, we contribute an evaluation framework for comparing Bitcoin key management approaches, and conduct a broad usability evaluation of six representative Bitcoin clients. We find that Bitcoin shares many of the fundamental challenges of key management known from other domains, but that Bitcoin may present a unique opportunity to rethink key management for end users.

cs.CR

IDIoT: Securing the Internet of Things like it's 1994

Over 20 billion Internet of Things devices are set to come online by 2020. Protecting such a large number of underpowered, UI-less, network-connected devices will require a new security paradigm. We argue that solutions dependent on vendor cooperation such as secure coding and platform changes are unlikely to provide adequate defenses for the majority of devices. Similarly, regulation approaches face a number implementation challenges which limit their effectiveness. As part of the new paradigm, we propose IDIoT, a network security policy enforcement framework for IoT devices. IDIoT prevents widespread network attacks by restricting IoT devices to only their necessary network behavior. IDIoT is simple and effective, building on decades of tried-and-true network security principles without requiring changes to the devices or cloud infrastructure.

cs.CR

Modeling Data-Plane Power Consumption of Future Internet Architectures

With current efforts to design Future Internet Architectures (FIAs), the evaluation and comparison of different proposals is an interesting research challenge. Previously, metrics such as bandwidth or latency have commonly been used to compare FIAs to IP networks. We suggest the use of power consumption as a metric to compare FIAs. While low power consumption is an important goal in its own right (as lower energy use translates to smaller environmental impact as well as lower operating costs), power consumption can also serve as a proxy for other metrics such as bandwidth and processor load. Lacking power consumption statistics about either commodity FIA routers or widely deployed FIA testbeds, we propose models for power consumption of FIA routers. Based on our models, we simulate scenarios for measuring power consumption of content delivery in different FIAs. Specifically, we address two questions: 1) which of the proposed FIA candidates achieves the lowest energy footprint; and 2) which set of design choices yields a power-efficient network architecture? Although the lack of real-world data makes numerous assumptions necessary for our analysis, we explore the uncertainty of our calculations through sensitivity analysis of input parameters.

cs.NI

Source Accountability with Domain-brokered Privacy

In an ideal network, every packet would be attributable to its sender, while host identities and transmitted content would remain private. Designing such a network is challenging because source accountability and communication privacy are typically viewed as conflicting properties. In this paper, we propose an architecture that guarantees source accountability and privacy-preserving communication by enlisting ISPs as accountability agents and privacy brokers. While ISPs can link every packet in their network to their customers, customer identity remains unknown to the rest of the Internet. In our architecture, network communication is based on Ephemeral Identifiers (EphIDs)---cryptographic tokens that can be linked to a source only by the source's ISP. We demonstrate that EphIDs can be generated and processed efficiently, and we analyze the practical considerations for deployment.

cs.NI