waashk/dblp huggingface dataset:
dsybil: optimal sybil-resistance for recommendation systems. recommendation systems can be attacked in various ways, and the ultimate attack form is reached with a {\em sybil attack}, where the attacker creates a potentially unlimited number of {\em sybil identities} to vote. defending against sybil attacks is often quite challenging, and the nature of recommendation systems makes it even harder. this paper presents {\em dsybil}, a novel defense for diminishing the influence of sybil identities in recommendation systems. dsybil provides strong provable guarantees that hold even under the worst-case attack and are optimal. dsybil can defend against an unlimited number of sybil identities over time. dsybil achieves its strong guarantees by i) exploiting the heavy-tail distribution of the typical voting behavior of the honest identities, and ii) carefully identifying whether the system is already getting ``enough help'' from the (weighted) voters already taken into account or whether more ``help'' is needed. our evaluation shows that dsybil would continue to provide high-quality recommendations even when a million-node botnet uses an optimal strategy to launch a sybil attack.
tempest in a teapot: compromising reflections revisited. reflecting objects such as tea pots and glasses, but also diffusely reflecting objects such as a user's shirt, can be used to spy on confidential data displayed on a monitor. first, we show how reflections in the user's eye can be exploited for spying on confidential data. second, we investigate to what extent monitor images can be reconstructed from the diffuse reflections on a wall or the user's clothes, and provide information-theoretic bounds limiting this type of attack. third, we evaluate the effectiveness of several countermeasures. this substantially improves previous work (backes et al., ieee symposium on security & privacy, 2008).
fingerprinting blank paper using commodity scanners. we develop a novel technique for authenticating physical documentsby using random, naturally occurring imperfections in paper texture.to this end, we devised a new method for measuring thethree-dimensional surface of a paper without modifying the documentin any way, using only a commodity scanner.from this physicalfeature, we generate a concise fingerprint that uniquely identifiesthe document.our method is secure against counterfeiting, robustto harsh handling, and applicable even before any content is printedon a page.it has a wide range of applications, including detectingforged currency and tickets, authenticating passports, and haltingcounterfeit goods.on a more sinister note, document identificationcould be used to de-anonymize printed surveys and to compromise thesecrecy of paper ballots.
it's no secret. measuring the security and reliability of authentication via "secret" questions. all four of the most popular webmail providers -- aol, google, microsoft, and yahoo! -- rely on personal questions as the secondary authentication secrets used to reset account passwords. the security of these questions has received limited formal scrutiny, almost all of which predates webmail. we ran a user study to measure the reliability and security of the questions used by all four webmail providers. we asked participants to answer these questions and then asked their acquaintances to guess their answers. acquaintances with whom participants reported being unwilling to share their webmail passwords were able to guess 17% of their answers. participants forgot 20% of their own answers within six months. what's more, 13% of answers could be guessed within five attempts by guessing the most popular answers of other participants, though this weakness is partially attributable to the geographic homogeneity of our participant pool.
pretty-bad-proxy: an overlooked adversary in browsers' https deployments. https is designed to provide secure web communications over insecure networks. the protocol itself has been rigorously designed and evaluated by assuming the network as an adversary. this paper is motivated by our curiosity about whether such an adversary has been carefully examined when https is integrated into the browser/web systems. we focus on a specific adversary named “pretty-bad-proxy” (pbp). pbp is a malicious proxy targeting browsers’ rendering modules above the http/https layer. it attempts to break the end-to-end security guarantees of https without breaking any cryptographic scheme. we discovered a set of vulnerabilities exploitable by a pbp: in many realistic network environments where attackers can sniff the browser traffic, they can steal sensitive data from an https server, fake an https page and impersonate an authenticated user to access an https server. these vulnerabilities reflect the neglects in the design of modern browsers – they affect multiple major browsers and a large number of websites. we believe that the pbp adversary has not been rigorously examined in the browser/web industry. the vendors of the affected browsers have all confirmed the vulnerabilities reported in this paper. most of them have patched or planned on patching their browsers. we believe the attack scenarios described in this paper may only be a subset of the vulnerabilities under pbp. thus further (and more rigorous) evaluations of the https deployments in browsers appear to be necessary.
wirelessly pickpocketing a mifare classic card. the mifare classic is the most widely used contactless smartcard on the market.the stream cipher crypto1 used by the classic has recently been reverse engineered and serious attacks have been proposed. the most serious of them retrieves a secret key in under a second. in order to clone a card, previously proposed attacks require that the adversary either has access to an eavesdropped communication session or executes a message-by-message man-in-the-middle attack between the victim and a legitimate reader. although this is already disastrous from a cryptographic point of view, system integrators maintain that these attacks cannot be performed undetected.this paper proposes four attacks that can be executed by an adversary having only wireless access to just a card (and not to a legitimate reader). the most serious of them recovers a secret key in less than a second on ordinary hardware. besides the cryptographic weaknesses, we exploit other weaknesses in the protocol stack. a vulnerability in the computation of parity bits allows an adversary to establish a side channel. another vulnerability regarding nested authentications provides enough plaintext for a speedy known-plaintext attack.
exploiting unix file-system races via algorithmic complexity attacks. we defeat two proposed unix file-system race condition defense mechanisms. first, we attack the probabilistic defense mechanism of tsafrir, et al., published at usenix fast 2008. we then show that the same attack breaks the kernel-based dynamic race detector of tsyrklevich and yee, published at usenix security 2003. we then argue that all kernel-based dynamic race detectors must have a model of the programs they protect or provide imperfect protection. the techniques we develop for performing these attacks work on multiple unix operating systems, on uni- and multi-processors, and are useful for exploiting most unix file-system races. we conclude that programmers should use provably-secure methods for avoiding race conditions when accessing the file-system.
disappearing mobile devices. in this paper, we extrapolate the evolution of mobile devices in one specific direction, namely miniaturization. while we maintain the concept of a device that people are aware of and interact with intentionally, we envision that this concept can become small enough to allow invisible integration into arbitrary surfaces or human skin, and thus truly ubiquitous use. this outcome assumed, we investigate what technology would be most likely to provide the basis for these devices, what abilities such devices can be expected to have, and whether or not devices that size can still allow for meaningful interaction. we survey candidate technologies, drill down on gesture-based interaction, and demonstrate how it can be adapted to the desired form factors. while the resulting devices offer only the bare minimum in feedback and only the most basic interactions, we demonstrate that simple applications remain possible. we complete our exploration with two studies in which we investigate the affordance of these devices more concretely, namely marking and text entry using a gesture alphabet.
perceptual interpretation of ink annotations on line charts. asynchronous collaborators often use freeform ink annotations to point to visually salient perceptual features of line charts such as peaks or humps, valleys, rising slopes and declining slopes. we present a set of techniques for interpreting such annotations to algorithmically identify the corresponding perceptual parts. our approach is to first apply a parts-based segmentation algorithm that identifies the visually salient perceptual parts in the chart. our system then analyzes the freeform annotations to infer the corresponding peaks, valleys or sloping segments. once the system has identified the perceptual parts it can highlight them to draw further attention and reduce ambiguity of interpretation in asynchronous collaborative discussions.
integrated videos and maps for driving directions. while onboard navigation systems are gaining in importance, maps are still the medium of choice for laying out a route to a destination and for way finding. however, even with a map, one is almost always more comfortable navigating a route the second time due to the visual memory of the route. to make the first time navigating a route feel more familiar, we present a system that integrates a map with a video automatically constructed from panoramic imagery captured at close intervals along the route. the routing information is used to create a variable speed video depicting the route. during playback of the video, the frame and field of view are dynamically modulated to highlight salient features along the route and connect them back to the map. a user interface is demonstrated to allow exploration of the combined map, video, and textual driving directions. we discuss the construction of the hybrid map and video interface. finally, we report the results of a study that provides evidence of the effectiveness of such a system for route following.
relaxed selection techniques for querying time-series graphs. time-series graphs are often used to visualize phenomena that change over time. common tasks include comparing values at different points in time and searching for specified patterns, either exact or approximate. however, tools that support time-series graphs typically separate query specification from the actual search process, allowing users to adapt the level of similarity only after specifying the pattern. we introduce relaxed selection techniques, in which users implicitly define a level of similarity that can vary across the search pattern, while creating a search query with a single-gesture interaction. users sketch over part of the graph, establishing the level of similarity through either spatial deviations from the graph, or the speed at which they sketch (temporal deviations). in a user study, participants were significantly faster when using our temporally relaxed selection technique than when using traditional techniques. in addition, they achieved significantly higher precision and recall with our spatially relaxed selection technique compared to traditional techniques.
arc-pad: absolute+relative cursor positioning for large displays with a mobile touchscreen. we introduce arc-pad (absolute+relative cursor pad), a novel technique for interacting with large displays using a mobile phone's touchscreen. in arc-pad we combine ab-solute and relative cursor positioning. tapping with arc-pad causes the cursor to jump to the corresponding location on the screen, providing rapid movement across large distances. for fine position control, users can also clutch using relative mode. unlike prior hybrid cursor positioning techniques, arc-pad does not require an explicit switch between relative and absolute modes. we compared arc-pad with the relative positioning commonly found on touchpads. users were given a target acquisition task on a large display, and results showed that they were faster with arc-pad, without sacrificing accuracy. users welcomed the benefits associated with arc-pad.
ripples: utilizing per-contact visualizations to improve user interaction with touch displays. we present ripples, a system which enables visualizations around each contact point on a touch display and, through these visualizations, provides feedback to the user about successes and errors of their touch interactions. our visualization system is engineered to be overlaid on top of existing applications without requiring the applications to be modified in any way, and functions independently of the application's responses to user input. ripples reduces the fundamental problem of ambiguity of feedback when an action results in an unexpected behaviour. this ambiguity can be caused by a wide variety of sources. we describe the ambiguity problem, and identify those sources. we then define a set of visual states and transitions needed to resolve this ambiguity, of use to anyone designing touch applications or systems. we then present the ripples implementation of visualizations for those states, and the results of a user study demonstrating user preference for the system, and demonstrating its utility in reducing errors.
sikuli: using gui screenshots for search and automation. we present sikuli, a visual approach to search and automation of graphical user interfaces using screenshots. sikuli allows users to take a screenshot of a gui element (such as a toolbar button, icon, or dialog box) and query a help system using the screenshot instead of the element's name. sikuli also provides a visual scripting api for automating gui interactions, using screenshot patterns to direct mouse and keyboard events. we report a web-based user study showing that searching by screenshot is easy to learn and faster to specify than keywords. we also demonstrate several automation tasks suitable for visual scripting, such as map navigation and bus tracking, and show how visual scripting can improve interactive help systems previously proposed in the literature.
the rise of the expert amateur: diy culture and citizen science. we are at an important technological inflection point. most of our computing systems have been designed and built by professionally trained experts (i.e. us--computer scientists, engineers, and designers) for use in specific domains and to solve explicit problems. artifacts often called "user manuals" traditionally prescribed the appropriate usage of these tools and implied an acceptable etiquette for interaction and experience. a fringe group of individuals usually labeled "hackers" or "nerds" have challenged this producer-consumer model of technology by hacking novel hardware and software features to "improve" our research and products while a similar creative group of technicians called "artists" have re-directed the techniques, tools, and tenets of accepted technological usage away from their typical manifestations in practicality and product. over time the technological artifacts of these fringe groups and the support for their rhetoric have gained them a foothold into computing culture and eroded the established power discontinuities within the practice of computing research. we now expect our computing tools to be driven by an architecture of open participation and democracy that encourages users to add value to their tools and applications as they use them. similarly, the bar for enabling the design of novel, personal computing systems and "hardware remixes" has fallen to the point where many non-experts and novices are readily embracing and creating fascinating and ingenious computing artifacts outside of our official and traditionally sanctioned academic research communities. but how have we as "expert" practitioners been influencing this discussion? by constructing a practice around the design and development of technology for task based and problem solving applications, we have unintentionally established such work as the status quo for the human computing experience. we have failed in our duty to open up alternate forums for technology to express itself and touch our lives beyond productivity and efficiency. blinded by our quest for "smart technologies" we have forgotten to contemplate the design of technologies to inspire us to be smarter, more curious, and more inquisitive. we owe it to ourselves to rethink the impact we desire to have on this historic moment in computing culture. we must choose to participate in and perhaps lead a dialogue that heralds an expansive new acceptable practice of designing to enable participation by experts and non-experts alike. we are in the milieu of the rise of the "expert amateur". we must change our mantra: "not just usability but usefulness and relevancy to our world, its citizens, and our environment". we must design for the world and what matters. this means discussing our computing research alongside new keywords such as the economy, the environment, activism, poverty, healthcare, famine, homelessness, literacy, religion, and politics. this talk will explore the design territory and potential opportunities for all of us to collaborate and benefit as a society from this cultural movement.
optically sensing tongue gestures for computer input. many patients with paralyzing injuries or medical conditions retain the use of their cranial nerves, which control the eyes, jaw, and tongue. while researchers have explored eye-tracking and speech technologies for these patients, we believe there is potential for directly sensing explicit tongue movement for controlling computers. in this paper, we describe a novel approach of using infrared optical sensors embedded within a dental retainer to sense tongue gestures. we describe an experiment showing our system effectively discriminating between four simple gestures with over 90% accuracy. in this experiment, users were also able to play the popular game tetris with their tongues. finally, we present lessons learned and opportunities for future work.
virtual shelves: interactions with orientation aware devices. triggering shortcuts or actions on a mobile device often requires a long sequence of key presses. because the functions of buttons are highly dependent on the current application's context, users are required to look at the display during interaction, even in many mobile situations when eyes-free interactions may be preferable. we present virtual shelves, a technique to trigger programmable shortcuts that leverages the user's spatial awareness and kinesthetic memory. with virtual shelves, the user triggers shortcuts by orienting a spatially-aware mobile device within the circular hemisphere in front of her. this space is segmented into definable and selectable regions along the phi and theta planes. we show that users can accurately point to 7 regions on the theta and 4 regions on the phi plane using only their kinesthetic memory. building upon these results, we then evaluate a proof-of-concept prototype of the virtual shelves using a nokia n93. the results show that virtual shelves is faster than the n93's native interface for common mobile phone tasks.
interactions in the air: adding further depth to interactive tabletops. although interactive surfaces have many unique and compelling qualities, the interactions they support are by their very nature bound to the display surface. in this paper we present a technique for users to seamlessly switch between interacting on the tabletop surface to above it. our aim is to leverage the space above the surface in combination with the regular tabletop display to allow more intuitive manipulation of digital content in three-dimensions. our goal is to design a technique that closely resembles the ways we manipulate physical objects in the real-world; conceptually, allowing virtual objects to be 'picked up' off the tabletop surface in order to manipulate their three dimensional position or orientation. we chart the evolution of this technique, implemented on two rear projection-vision tabletops. both use special projection screen materials to allow sensing at significant depths beyond the display. existing and new computer vision techniques are used to sense hand gestures and postures above the tabletop, which can be used alongside more familiar multi-touch interactions. interacting above the surface in this way opens up many interesting challenges. in particular it breaks the direct interaction metaphor that most tabletops afford. we present a novel shadow-based technique to help alleviate this issue. we discuss the strengths and limitations of our technique based on our own observations and initial user feedback, and provide various insights from comparing, and contrasting, our tabletop implementations
a practical pressure sensitive computer keyboard. a pressure sensitive computer keyboard is presented that independently senses the force level on every depressed key. the design leverages existing membrane technologies and is suitable for low-cost, high-volume manufacturing. a number of representative applications are discussed.
a reconfigurable ferromagnetic input device. we present a novel hardware device based on ferromagnetic sensing, capable of detecting the presence, position and deformation of any ferrous object placed on or near its surface. these objects can include ball bearings, magnets, iron filings, and soft malleable bladders filled with ferrofluid. our technology can be used to build reconfigurable input devices -- where the physical form of the input device can be assembled using combinations of such ferrous objects. this allows users to rapidly construct new forms of input device, such as a trackball-style device based on a single large ball bearing, tangible mixers based on a collection of sliders and buttons with ferrous components, and multi-touch malleable surfaces using a ferrofluid bladder. we discuss the implementation of our technology, its strengths and limitations, and potential application scenarios.
user guided audio selection from complex sound mixtures. in this paper we present a novel interface for selecting sounds in audio mixtures. traditional interfaces in audio editors provide a graphical representation of sounds which is either a waveform, or some variation of a time/frequency transform. although with these representations a user might be able to visually identify elements of sounds in a mixture, they do not facilitate object-specific editing (e.g. selecting only the voice of a singer in a song). this interface uses audio guidance from a user in order to select a target sound within a mixture. the user is asked to vocalize (or otherwise sonically represent) the desired target sound, and an automatic process identifies and isolates the elements of the mixture that best relate to the user's input. this way of pointing to specific parts of an audio stream allows a user to perform audio selections which would have been infeasible otherwise.
abracadabra: wireless, high-precision, and unpowered finger input for very small mobile devices. we present abracadabra, a magnetically driven input technique that offers users wireless, unpowered, high fidelity finger input for mobile devices with very small screens. by extending the input area to many times the size of the device's screen, our approach is able to offer a high c-d gain, enabling fine motor control. additionally, screen occlusion can be reduced by moving interaction off of the display and into unused space around the device. we discuss several example applications as a proof of concept. finally, results from our user study indicate radial targets as small as 16 degrees can achieve greater than 92% selection accuracy, outperforming comparable radial, touch-based finger input.