Computer Sciences Commons^™

Fingerprinting Ieee 802.15.4 Devices With Commodity Radios, Ira Ray Jenkins, Rebecca Shapiro, Sergey Bratus, Ryan Speers, Travis Goodspeed

Computer Science Technical Reports

We present a reliable method of PHY-layer fingerprinting of IEEE 802.15.4-conformant nodes with commodity digital radio chips widely used in building inexpensive IEEE 802.15.4-conformant devices. Typically, PHY-layer fingerprinting requires software-defined radios that cost orders of magnitude more than the chips they can fingerprint; our method does not require a software-defined radio and uses the same inexpensive chips. For mission-critical systems relying on 802.15.4 devices, defense-in-depth is thus necessary. Device fingerprinting has long been an important defensive tool; reducing its cost raises its utility for defenders. We investigate new methods of fingerprinting 802.15.4 devices by exploring techniques to differentiate between multiple …

Speaking The Local Dialect: Exploiting Differences Between Ieee 802.15.4 Receivers With Commodity Radios For Fingerprinting, Targeted Attacks, And Wids Evasion, Ira Ray Jenkins, Rebecca Shapiro, Sergey Bratus, Travis Goodspeed, Ryan Speers, David Dowd

Computer Science Technical Reports

Producing IEEE 802.15.4 PHY-frames reliably accepted by some digital radio receivers, but rejected by others---depending on the receiver chip's make and model---has strong implications for wireless security. Attackers could target specific receivers by crafting "shaped charges," attack frames that appear valid to the intended target and are ignored by all other recipients. By transmitting in the unique, slightly non-compliant "dialect" of the intended receivers, attackers would be able to create entire communication streams invisible to others, including wireless intrusion detection and prevention systems (WIDS/WIPS).

These scenarios are no longer theoretic. We present methods of producing such IEEE 802.15.4 frames with …

A Computational Approach To Qualitative Analysis In Large Textual Datasets, Michael Evans

Dartmouth Scholarship

In this paper I introduce computational techniques to extend qualitative analysis into the study of large textual datasets. I demonstrate these techniques by using probabilistic topic modeling to analyze a broad sample of 14,952 documents published in major American newspapers from 1980 through 2012. I show how computational data mining techniques can identify and evaluate the significance of qualitatively distinct subjects of discussion across a wide range of public discourse. I also show how examining large textual datasets with computational methods can overcome methodological limitations of conventional qualitative methods, such as how to measure the impact of particular cases on …

Vocal Resonance As A Passive Biometric, Cory Cornelius, Zachary Marois, Jacob Sorber, Ron Peterson, Shrirang Mare, David Kotz

Computer Science Technical Reports

We anticipate the advent of body-area networks of pervasive wearable devices, whether for health monitoring, personal assistance, entertainment, or home automation. In our vision, the user can simply wear the desired set of devices, and they "just work"; no configuration is needed, and yet they discover each other, recognize that they are on the same body, configure a secure communications channel, and identify the user to which they are attached. This paper addresses a method to achieve the latter, that is, for a wearable device to identify the wearer, allowing sensor data to be properly labeled or personalized behavior to …

From Map To Dist: The Evolution Of A Large-Scale Wlan Monitoring System, Keren Tan, Chris Mcdonald, Bennet Vance, Chrisil Arackaparambil, Sergey Bratus, David Kotz

Dartmouth Scholarship

The edge of the Internet is increasingly becoming wireless. Therefore, monitoring the wireless edge is important to understanding the security and performance aspects of the Internet experience. We have designed and implemented a large-scale WLAN monitoring system, the Distributed Internet Security Testbed (DIST), at Dartmouth College. It is equipped with distributed arrays of “sniffers” that cover 210 diverse campus locations and more than 5,000 users. In this paper, we describe our approach, designs and solutions for addressing the technical challenges that have resulted from efficiency, scalability, security, and management perspectives. We also present extensive evaluation results on a production network, …

Securing Information Technology In Healthcare, Denise Anthony, Andrew T. Campbell, Thomas Candon, Andrew Gettinger, David Kotz, Lisa A. Marsch, Andrés Molina-Markham, Karen M. Page, Sean W. Smith, Carl A. Gunter, M. Eric Johnson

Dartmouth Scholarship

Information technology (IT) has great potential to improve healthcare quality while also improving efficiency, and thus has been a major focus of recent healthcare reform efforts. However, developing, deploying and using IT that is both secure and genuinely effective in the complex clinical, organizational and economic environment of healthcare is a significant challenge. Further, it is imperative that we better understand the privacy concerns of patients and providers, as well as the ability of current technologies, policies, and laws to adequately protect privacy. The Securing Information Technology in Healthcare (SITH) workshops were created to provide a forum to discuss security …

Access Control In And For The Real World, Sara Sinclair

Dartmouth College Ph.D Dissertations

Access control is a core component of any information-security strategy. Researchers have spent tremendous energy over the past forty years defining abstract access-control models and proving various properties about them. However, surprisingly little attention has been paid to how well these models work in real socio-technical systems (i.e., real human organizations). This dissertation describes the results of two qualitative studies (involving 52 participants from four companies, drawn from the financial, software, and healthcare sectors) and observes that the current practice of access control is dysfunctional at best. It diagnoses the broken assumptions that are at the heart of this dysfunction, …

Flexiterm: A Flexible Term Recognition Method, Irena Spasić, Mark Greenwood, Alun Preece, Nick Francis, Glyn Elwyn

Dartmouth Scholarship

Background: The increasing amount of textual information in biomedicine requires effective term recognition methods to identify textual representations of domain-specific concepts as the first step toward automating its semantic interpretation. The dictionary look-up approaches may not always be suitable for dynamic domains such as biomedicine or the newly emerging types of media such as patient blogs, the main obstacles being the use of non-standardised terminology and high degree of term variation.

Grid Cryptographic Simulation: A Simulator To Evaluate The Scalability Of The X.509 Standard In The Smart Grid, Tucker L. Ward

Dartmouth College Undergraduate Theses

PKI may be pushed beyond known limits when scaled to some visions of the smart grid; our research developed a simulation, Grid Cryptographic Simulation (GCS), to evaluate these potential issues, identify cryptographic bottlenecks, and evaluate tradeoffs between performance and security. Ultimately, GCS can be used to identify scalability challenges and suggest improvements to make PKI more efficient, effective, and scalable before it is deployed in the envisioned smart grid.

Usable Security For Wireless Body-Area Networks, Cory Cornelius

Dartmouth College Ph.D Dissertations

We expect wireless body-area networks of pervasive wearable devices will enable in situ health monitoring, personal assistance, entertainment personalization, and home automation. As these devices become ubiquitous, we also expect them to interoperate. That is, instead of closed, end-to-end body-worn sensing systems, we envision standardized sensors that wirelessly communicate their data to a device many people already carry today, the smart phone. However, this ubiquity of wireless sensors combined with the characteristics they sense present many security and privacy problems. In this thesis we describe solutions to two of these problems. First, we evaluate the use of bioimpedance for recognizing …

Elfbac: Using The Loader Format For Intent-Level Semantics And Fine-Grained Protection, Julian Bangert, Sergey Bratus, Rebecca Shapiro, Michael E. Locasto, Jason Reeves, Sean W. Smith, Anna Shubina

Computer Science Technical Reports

Adversaries get software to do bad things by rewriting memory and changing control flow. Current approaches to protecting against these attacks leave many exposures; for example, OS-level filesystem protection and OS/architecture support of the userspace/kernelspace distinction fail to protect corrupted userspace code from changing userspace data. In this paper we present a new approach: using the ELF/ABI sections already produced by the standard binary toolchain to define, specify, and enforce fine-grained policy within an application's address space. We experimentally show that enforcement of such policies would stop a large body of current attacks and discuss ways we could extend existing …

Please Take My Survey: Compliance With Smartphone-Based Ema/Esm Studies, Shloka R. Kini

Dartmouth College Undergraduate Theses

This thesis analyzes the factors that affect compliance in Ecological Momentary Assessment (EMA) survey systems using smartphones. Current EMA systems have simple parameters in their triggering mechanisms, which results in missed or ignored surveys, creating a loss of subject data. Over the course of three user studies, with slight variations, we analyze the factors that influence the willingness of a survey participant to answer surveys on an Android phone. An understanding of these factors would be valuable for mobile developers in developing advanced EMA trigger systems. After having experienced various unforeseen challenges in the process, we describe the parameters and …

Nimbus A Novel Multi-Device Operating System Shell, Sang Jin Lee

Dartmouth College Undergraduate Theses

Web technologies have advanced considerably in the last decade. With the introduction of HTML5 and CSS3 web standards, websites are no longer static documents, but rich applications that are capable of rivaling those written in native code. Similarly, internet infrastructure and adoption has reached a point where "always connected" and cross-platform applications such as Facebook, Twitter, Google Drive, Spotify, Dropbox, and Youtube are becoming dominant. While these web applications have acclimated users to cross-platform and cross-device experiences, operating systems have lagged behind, offering subpar experiences across devices. We present the design, prototype implementation, and evaluation of Nimbus, an operating system …

An Algorithm For Computing Edge Colorings On Regular Bipartite Multigraphs, Andrew S. Hannigan

Dartmouth College Undergraduate Theses

In this paper, we consider the problem of finding an edge coloring of a d-regular bipartite multigraph with 2n vertices and m=nd edges. The best known deterministic algorithm (by Cole, Ost, and Schirra) takes O(m log d) time to find an edge coloring of such a graph. This bound is achieved by combining an O(m)-time perfect-matching algorithm with the Euler partition algorithm. The O(m) time bound on the Cole, Ost, and Schirra perfect-matching algorithm has been shown to be optimal. In this paper we present an alternative perfect-matching algorithm called QuickMatch. Empirical analysis shows that QuickMatch finds a perfect matching …

Ekho: A Tool For Recording And Emulating Energy Harvesting Conditions, Ryan H. Archer

Dartmouth College Undergraduate Theses

Harvested energy makes it possible to deploy sensing devices long-term with minimal required upkeep. However, as devices shrink, unpredictable power supplies make it difficult for system designers to anticipate the behavior of these devices. Ekho is tool that records and emulates energy harvesting conditions in order to enable accurate and repeatable testing of these sensing devices. Ekho uses the concept of I-V curves — curves that describe harvesting current in relation to supply voltage — in order to accurately represent harvesting conditions in a form that is independent of the sensing platform and the type of energy that is being …

Mobile Applications: Games That Transform Education, Edward Y. Zhang

Dartmouth College Undergraduate Theses

A breakthrough development in the crossing of education and technology has long been a subject of heated debate. The possibility of combining machine learning and attention-grabbing graphics to not only make learning easy and interesting, but personalized, was the original impetus for gamifying education. In this paper I investigate the history of technology and media through the lens of education, and attempt to apply the principles, practices, and insights gleaned there within to an educational mobile game. Specifically, the mobile app I designed for the iPhone and Android operating systems focuses on teaching players SAT I math concepts using Nintendo’s …

Polynomial And Query Complexity Of Minterm-Cyclic Functions, Matthew J. Harding

Dartmouth College Undergraduate Theses

Boolean functions are at the heart of all computations, and all Boolean functions can be reduced to a sum of pattern-matching functions, called minterm-cyclic functions. In this thesis, we examine properties of polynomials representing minterm-cyclic Boolean functions. We use the term "saturated" to represent a polynomial with degree equal to input size n for all n; this indicates the intuitive notion that such functions are in some way complex, or difficult to compute. We present three main results. Firstly, there exist an infinite number of monotone minterm-cyclic functions that are not saturated. Secondly, for a specific class of minterms called …

Interpreting And Reconstructing Data From Sensor Networks, Jonathan H. Guinther

Computer Science Technical Reports

Geophysical phenomena are often three-dimensional, time-variant, and physically large, making them difficult to measure. As wireless sensor nodes become cheaper, smaller, and more powerful, using a sensor swarm as a sampling framework seems to be a viable approach to this problem. However, samples from the network can be sparse and unstructured, creating an incomplete picture. Thus, the question addressed by this project is the following: How can we easily construct and interpret the best model of the underlying reality over some domain, given a possibly sparse and irregular set of samples? We present the design, implementation, and evaluation of the …

Geometrical And Probabilistic Methods For Determining Association Models And Structures Of Protein Complexes, Himanshu Chandola

Dartmouth College Ph.D Dissertations

Protein complexes play vital roles in cellular processes within living organisms. They are formed by interactions between either different proteins (hetero-oligomers) or identical proteins (homo-oligomers). In order to understand the functions of the complexes, it is important to know the manner in which they are assembled from the component subunits and their three dimensional structure. This thesis addresses both of these questions by developing geometrical and probabilistic methods for analyzing data from two complementary experiment types: Small Angle Scattering (SAS) and Nuclear Magnetic Resonance (NMR) spectroscopy. Data from an SAS experiment is a set of scattering intensities that can give …

Sampling For Complexity In Rendering, Jiawei Ou

Dartmouth College Ph.D Dissertations

As the visual effect and movie industries are striving for realism and high fidelity images, physically based lighting, global illumination, realistic materials, and highly tessellated geometry are gradually accepted and used in movie and game industries. Modern computer graphics has reached an unprecedented level of complexity. As a result, brute-force rendering methods become prohibitively expensive. For decades, computer graphics researchers have been tackling the complexity in rendering by introducing more advanced Monte Carlo integrators, efficient sampling and reconstruction algorithms, effective filtering techniques, sophisticated data structures, and new hardware architectures. In this thesis, we focus on deriving better sampling algorithms to …

Photo Forensics From Partial Constraints, Eric R. Kee

Dartmouth College Ph.D Dissertations

A variety of forensic methods have been developed to identify falsified photos, each unified by the ability to estimate and detect properties of a photo that are perturbed by forgery. There exist, however, many photos in which the required properties cannot be estimated. We present an approach to detect forgery in these photos. We use this approach to detect physically inconsistent shadows and shading in photos for which it is not possible to estimate the associated lighting properties. Specifically, we develop a method to detect inconsistent shadows cast by point and area light sources when a strict shadow-to-object correspondence cannot …

Security-Policy Analysis With Extended Unix Tools, Gabriel A. Weaver

Dartmouth College Ph.D Dissertations

During our fieldwork with real-world organizations---including those in Public Key Infrastructure (PKI), network configuration management, and the electrical power grid---we repeatedly noticed that security policies and related security artifacts are hard to manage. We observed three core limitations of security policy analysis that contribute to this difficulty. First, there is a gap between policy languages and the tools available to practitioners. Traditional Unix text-processing tools are useful, but practitioners cannot use these tools to operate on the high-level languages in which security policies are expressed and implemented. Second, practitioners cannot process policy at multiple levels of abstraction but they need …

Mexsvms: Mid-Level Features For Scalable Action Recognition, Du Tran, Lorenzo Torresani

Computer Science Technical Reports

This paper introduces MEXSVMs, a mid-level representation enabling efficient recognition of actions in videos. The entries in our descriptor are the outputs of several movement classifiers evaluated over spatial-temporal volumes of the image sequence, using space-time interest points as low-level features. Each movement classifier is a simple exemplar-SVM, i.e., an SVM trained using a single positive video and a large number of negative sequences. Our representation offers two main advantages. First, since our mid-level features are learned from individual video exemplars, they require minimal amount of supervision. Second, we show that even simple linear classification models trained on our global …

Privacy In Mobile Technology For Personal Healthcare, Sasikanth Avancha, Amit Baxi, David Kotz

Dartmouth Scholarship

Information technology can improve the quality, efficiency, and cost of healthcare. In this survey, we examine the privacy requirements of \emphmobile\/ computing technologies that have the potential to transform healthcare. Such \emphmHealth\/ technology enables physicians to remotely monitor patients' health, and enables individuals to manage their own health more easily. Despite these advantages, privacy is essential for any personal monitoring technology. Through an extensive survey of the literature, we develop a conceptual privacy framework for mHealth, itemize the privacy properties needed in mHealth systems, and discuss the technologies that could support privacy-sensitive mHealth systems. We end with a list of …

An Optimal Lower Bound On The Communication Complexity Of Gap-Hamming-Distance, Amit Chakrabarti, Oded Regev

Dartmouth Scholarship

We prove an optimal Ω(n) lower bound on the randomized communication complex- ity of the much-studied gap-hamming-distance problem. As a consequence, we obtain essentially optimal multipass space lower bounds in the data stream model for a number of fundamental prob- lems, including the estimation of frequency moments. The gap-hamming-distance problem is a communication problem, wherein Alice and Bob receive n-bit strings x and y, respectively. They are promised that the Hamming distance between x and y is either at least n/2 + √n or at most n, and their goal is to decide which of these is the case. Since …

Understanding Sharing Preferences And Behavior For Mhealth Devices, Aarathi Prasad, Jacob Sorber, Timothy Stablein, Denis Anthony, David Kotz

Dartmouth Scholarship

mHealth devices offer many potential benefits to patients, health providers and others involved in the patients' healthcare. If patients are not in control of the collection and sharing of their personal health information, they will have privacy concerns even while enjoying the benefits of the devices. We investigated patients' willingness to share their personal health information, collected using mHealth devices, with their family, friends, third parties and the public. Our findings are based on a user study conducted with 41 participants. The best way to understand people's privacy concerns is to give them the opportunity to use the device and …

Who Wears Me? Bioimpedance As A Passive Biometric, Cory Cornelius, Jacob Sorber, Ronald Peterson, Joe Skinner, Ryan Halter, David Kotz

Dartmouth Scholarship

Mobile and wearable systems for monitoring health are becoming common. If such an mHealth system knows the identity of its wearer, the system can properly label and store data collected by the system. Existing recognition schemes for such mobile applications and pervasive devices are not particularly usable – they require ıt active engagement with the person (e.g., the input of passwords), or they are too easy to fool (e.g., they depend on the presence of a device that is easily stolen or lost). \par We present a wearable sensor to passively recognize people. Our sensor uses the unique electrical properties …

Privacy-Preserving Screen Capture: Closing The Loop For Medical Informatics Usability, Joseph Cooley, Sean Smith

Computer Science Technical Reports

As information technology permeates healthcare (particularly provider-facing systems), maximizing system effectiveness requires the ability to document and analyze tricky or troublesome usage scenarios. However, real-world medical applications are typically replete with privacy-sensitive data regarding patients, diagnoses, clinicians, and EMR user interface details; any instrumentation for screen capture (capturing and recording the scenario depicted on the screen) needs to respect these privacy constraints. Furthermore, real-world medical informatics systems are typically composed of modules from many sources, mission-critical and often closed-source; any instrumentation for screen capture cannot rely on access to structured output or software internals. In this paper, we present a …

Methods Of Computing Deque Sortable Permutations Given Complete And Incomplete Information, Daniel J. Denton

Dartmouth College Undergraduate Theses

The problem of determining which permutations can be sorted using certain switchyard networks is a venerable problem in computer science dating back to Knuth in 1968. In this work, we are interested in permutations which are sortable on a double-ended queue (called a deque), or on two parallel stacks. In 1982, Rosenstiehl and Tarjan presented an O(n) algorithm for testing whether a given permutation was sortable on parallel stacks. In the same paper, they also presented a modification giving O(n) test for sortability on a deque. We demonstrate a slight error in the version of their algorithm for testing deque …

Search For Trust: An Analysis And Comparison Of Ca System Alternatives And Enhancements, Alexandra C. Grant

Dartmouth College Undergraduate Theses

The security of the Public Key Infrastructure has been reevaluated in response to Certification Authority (CA) compromise which resulted in the circulation of fraudulent certificates. These rogue certificates can and have been used to execute Man-in-the-Middle attacks and gain access to users’ sensitive information. In wake of these events, there has been a call for change to the extent of either securing the current system or altogether replacing it with an alternative design. This paper will explore the following proposals which have been put forth to replace or improve the CA system with the goal of aiding in the prevention …