Virtual Reality Observations: Using Virtual Reality to Augment Lab-Based Shoulder Surfing Research

Given the difficulties of studying the shoulder surfing resistance of authentication systems in a live setting, researchers often ask study participants to shoulder surf authentications by watching two-dimensional (2D) video recordings of a user authenticating. How-ever, these video recordings do not provide participants with a realistic shoulder surfing experience, creating uncertainty in the value and validity of lab-based shoulder surfing experiments. In this work, we exploit the unique characteristics of virtual reality (VR) and study the use of non-immersive/immersive VR recordings for shoulder surfing research. We conducted a user study (N=18) to explore the strengths and weaknesses of such a VR-based shoulder surfing research approach. Our results suggest that immersive VR observations result in a more realistic shoulder surfing experience, in a significantly higher sense of being part of the authentication environment, in a greater feeling of spatial presence, and in a higher level of involvement than 2D video observations without impacting participants’ observation performance. This suggests that studying shoulder surfing in VR is advantageous in many ways compared to currently used approaches, e.g., participants can freely choose their observation angle rather than being limited to a fixed observation angle as done in current methods. We discuss the strengths and weaknesses of using VR for shoulder surfing research and conclude with four recommendations to help researchers decide when (and when not) to employ VR for shoulder surfing research in the authentication research domain

I (don\u27t) see what you typed there! Shoulder-surfing resistant password entry on gamepads

Using gamepad-driven devices like games consoles is an activity frequently shared with others. Thus, shoulder-surfing is a serious threat. To address this threat, we present the first investigation of shoulder-surfing resistant text password entry on gamepads by (1) identifying the requirements of this context; (2) assessing whether shoulder-surfing resistant authentication schemes proposed in non-gamepad contexts can be viably adapted to meet these requirements; (3) proposing ``Colorwheels\u27\u27, a novel shoulder-surfing resistant authentication scheme specifically geared towards this context; (4) using two different methodologies proposed in the literature for evaluating shoulder-surfing resistance to compare ``Colorwheels\u27\u27, on-screen keyboards (the de facto standard in this context), and an existing shoulder-surfing resistant scheme which we identified during our assessment and adapted for the gamepad context; (5) evaluating all three schemes regarding their usability. Having applied different methodologies to measure shoulder-surfing resistance, we discuss their strengths and pitfalls and derive recommendations for future research

Building and evaluating an inconspicuous smartphone authentication method

Tese de mestrado em Engenharia Informática, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2013Os smartphones que trazemos connosco estão cada vez mais entranhados nas nossas vidas intimas. Estes dispositivos possibilitam novas formas de trabalhar, de socializar, e ate de nos divertirmos. No entanto, também criaram novos riscos a nossa privacidade. Uma forma comum de mitigar estes riscos e configurar o dispositivo para bloquear apos um período de inatividade. Para voltar a utiliza-lo, e então necessário superar uma barreira de autenticação. Desta forma, se o aparelho cair das mãos de outra pessoa, esta não poderá utiliza-lo de forma a que tal constitua uma ameaça. O desbloqueio com autenticação e, assim, o mecanismo que comummente guarda a privacidade dos utilizadores de smartphones. Porem, os métodos de autenticação atualmente utilizados são maioritariamente um legado dos computadores de mesa. As palavras-passe e códigos de identificação pessoal são tornados menos seguros pelo facto de as pessoas criarem mecanismos para os memorizarem mais facilmente. Alem disso, introduzir estes códigos e inconveniente, especialmente no contexto móvel, em que as interações tendem a ser curtas e a necessidade de autenticação atrapalha a prossecução de outras tarefas. Recentemente, os smartphones Android passaram a oferecer outro método de autenticação, que ganhou um grau de adoção assinalável. Neste método, o código secreto do utilizador e uma sucessão de traços desenhados sobre uma grelha de 3 por 3 pontos apresentada no ecrã táctil. Contudo, quer os códigos textuais/numéricos, quer os padrões Android, são suscetíveis a ataques rudimentares. Em ambos os casos, o canal de entrada e o toque no ecrã táctil; e o canal de saída e o visual. Tal permite que outras pessoas possam observar diretamente a introdução da chave; ou que mais tarde consigam distinguir as marcas deixadas pelos dedos na superfície de toque. Alem disso, estes métodos não são acessíveis a algumas classes de utilizadores, nomeadamente os cegos. Nesta dissertação propõe-se que os métodos de autenticação em smartphones podem ser melhor adaptados ao contexto móvel. Nomeadamente, que a possibilidade de interagir com o dispositivo de forma inconspícua poderá oferecer aos utilizadores um maior grau de controlo e a capacidade de se auto-protegerem contra a observação do seu código secreto. Nesse sentido, foi identificada uma modalidade de entrada que não requer o canal visual: sucessões de toques independentes de localização no ecrã táctil. Estes padrões podem assemelhar-se (mas não estão limitados) a ritmos ou código Morse. A primeira contribuição deste trabalho e uma técnica algorítmica para a deteção destas sucessões de toques, ou frases de toque, como chaves de autenticação. Este reconhecedor requer apenas uma demonstração para configuração, o que o distingue de outras abordagens que necessitam de vários exemplos para treinar o algoritmo. O reconhecedor foi avaliado e demonstrou ser preciso e computacionalmente eficiente. Esta contribuição foi enriquecida com o desenvolvimento de uma aplicação Android que demonstra o conceito. A segunda contribuição e uma exploração de fatores humanos envolvidos no uso de frases de toque para autenticação. E consubstanciada em três estudos com utilizadores, em que o método de autenticação proposto e comparado com as alternativas mais comuns: PIN e o padrão Android. O primeiro estudo (N=30) compara os três métodos no que que diz respeito a resistência a observação e à usabilidade, entendida num sentido lato, que inclui a experiencia de utilização (UX). Os resultados sugerem que a usabilidade das três abordagens e comparável, e que em condições de observação perfeitas, nos três casos existe grande viabilidade de sucesso para um atacante. O segundo estudo (N=19) compara novamente os três métodos mas, desta feita, num cenário de autenticação inconspícua. Com efeito, os participantes tentaram introduzir os códigos com o dispositivo situado por baixo de uma mesa, fora do alcance visual. Neste caso, demonstra-se que a autenticação com frases de toque continua a ser usável. Já com as restantes alternativas existe uma diminuição substancial das medidas de usabilidade. Tal sugere que a autenticação por frases de toque suporta a capacidade de interação inconspícua, criando assim a possibilidade de os utilizadores se protegerem contra possíveis atacantes. O terceiro estudo (N=16) e uma avaliação de usabilidade e aceitação do método de autenticação com utilizadores cegos. Neste estudo, são também elicitadas estratégias de ocultação suportadas pela autenticação por frases de toque. Os resultados sugerem que a técnica e também adequada a estes utilizadores.As our intimate lives become more tangled with the smartphones we carry, privacy has become an increasing concern. A widely available option to mitigate security risks is to set a device so that it locks after a period of inactivity, requiring users to authenticate for subsequent use. Current methods for establishing one's identity are known to be susceptible to even rudimentary observation attacks. The mobile context in which interactions with smartphones are prone to occur further facilitates shoulder-surfing. We submit that smartphone authentication methods can be better adapted to the mobile context. Namely, the ability to interact with the device in an inconspicuous manner could offer users more control and the ability to self-protect against observation. Tapping is a communication modality between a user and a device that can be appropriated for that purpose. This work presents a technique for employing sequences of taps, or tap phrases, as authentication codes. An efficient and accurate tap phrase recognizer, that does not require training, is presented. Three user studies were conducted to compare this approach to the current leading methods. Results indicate that the tapping method remains usable even under inconspicuous authentications scenarios. Furthermore, we found that it is appropriate for blind users, to whom usability barriers and security risks are of special concern

Towards Baselines for Shoulder Surfing on Mobile Authentication

Given the nature of mobile devices and unlock procedures, unlock authentication is a prime target for credential leaking via shoulder surfing, a form of an observation attack. While the research community has investigated solutions to minimize or prevent the threat of shoulder surfing, our understanding of how the attack performs on current systems is less well studied. In this paper, we describe a large online experiment (n=1173) that works towards establishing a baseline of shoulder surfing vulnerability for current unlock authentication systems. Using controlled video recordings of a victim entering in a set of 4- and 6-length PINs and Android unlock patterns on different phones from different angles, we asked participants to act as attackers, trying to determine the authentication input based on the observation. We find that 6-digit PINs are the most elusive attacking surface where a single observation leads to just 10.8% successful attacks, improving to 26.5\% with multiple observations. As a comparison, 6-length Android patterns, with one observation, suffered 64.2% attack rate and 79.9% with multiple observations. Removing feedback lines for patterns improves security from 35.3\% and 52.1\% for single and multiple observations, respectively. This evidence, as well as other results related to hand position, phone size, and observation angle, suggests the best and worst case scenarios related to shoulder surfing vulnerability which can both help inform users to improve their security choices, as well as establish baselines for researchers.Comment: Will appear in Annual Computer Security Applications Conference (ACSAC

Developing and evaluating a gestural and tactile mobile interface to support user authentication

As awareness grows surrounding the importance of protecting sensitive data, stored on or accessed through a mobile device, a need has been identified to develop authentication schemes which better match the needs of users, and are more resistant to observer attacks. This paper describes the design and evaluation of H4Plock (pronounced “Hap-lock”), a novel authentication mechanism to address the situation. In order to authenticate, the user enters up to four pre-selected on-screen gestures, informed by tactile prompts. The system has been designed in such a way that the sequence of gestures will vary on each authentication attempt, reducing the capability of a shoulder surfer to recreate entry. 94.1% of participants were able to properly authenticate using H4Plock, with 73.3% successfully accessing the system after a gap of five days without rehearsal. Only 23.5% of participants were able to successfully recreate passcodes in a video-based attack scenario, where gestures were unique in design and entered at different locations around the interface

Secure and Usable User Authentication

Authentication is a ubiquitous task in users\u27 daily lives. The dominant form of user authentication are text passwords. They protect private accounts like online banking, gaming, and email, but also assets in organisations. Yet, many issues are associated with text passwords, leading to challenges faced by both, users and organisations. This thesis contributes to the body of research enabling secure and usable user authentication, benefiting both, users and organisations. To that end, it addresses three distinct challenges. The first challenge addressed in this thesis is the creation of correct, complete, understandable, and effective password security awareness materials. To this end, a systematic process for the creation of awareness materials was developed and applied to create a password security awareness material. This process comprises four steps. First, relevant content for an initial version is aggregated (i.e. descriptions of attacks on passwords and user accounts, descriptions of defences to these attacks, and common misconceptions about password and user account security). Then, feedback from information security experts is gathered to ensure the correctness and completeness of the awareness material. Thereafter, feedback from lay-users is gathered to ensure the understandability of the awareness material. Finally, a formal evaluation of the awareness material is conducted to ensure its effectiveness (i.e. whether the material improves participant\u27s ability to assess the security of passwords as well as password-related behaviour and decreases the prevalence of common misconceptions about password and user account security). The results of the evaluation show the effectiveness of the awareness material: it significantly improved the participants\u27 ability to assess the security of password-related behaviour as well as passwords and significantly decreased the prevalence of misconceptions about password and user account security. The second challenge addressed in this thesis is shoulder-surfing resistant text password entry with gamepads (as an example of very constrained input devices) in shared spaces. To this end, the very first investigation of text password entry with gamepads is conducted. First, the requirements of authentication in the gamepad context are described. Then, these requirements are applied to assess schemes already deployed in the gamepad context and shoulder-surfing resistant authentication schemes from the literature proposed for non-gamepad contexts. The results of this assessment show that none of the currently deployed and only four of the proposals in the literature fulfil all requirements. Furthermore, the results of the assessment also indicate a need for an empirical evaluation in order to exactly gauge the shoulder-surfing threat in the gamepad context and compare alternatives to the incumbent on-screen keyboard. Based on these results, two user studies (one online study and one lab study) are conducted to investigate the shoulder-surfing resistance and usability of three authentication schemes in the gamepad context: the on-screen keyboard (as de-facto standard in this context), the grid-based scheme (an existing proposal from the literature identified as the most viable candidate adaptable to the gamepad context during the assessment), and Colorwheels (a novel shoulder-surfing resistant authentication scheme specifically designed for the gamepad context). The results of these two user studies show that on-screen keyboards are highly susceptible to opportunistic shoulder-surfing, but also show the most favourable usability properties among the three schemes. Colorwheels offers the most robust shoulder-surfing resistance and scores highest with respect to participants\u27 intention to use it in the future, while showing more favourable usability results than the grid-based scheme. The third challenge addressed in this thesis is secure and efficient storage of passwords in portfolio authentication schemes. Portfolio authentication is used to counter capture attacks such as shoulder-surfing or eavesdropping on network traffic. While usability studies of portfolio authentication schemes showed promising results, a verification scheme which allows secure and efficient storage of the portfolio authentication secret had been missing until now. To remedy this problem, the (t,n)-threshold verification scheme is proposed. It is based on secret sharing and key derivation functions. The security as well as the efficiency properties of two variants of the scheme (one based on Blakley secret sharing and one based on Shamir secret sharing) are evaluated against each other and against a naive approach. These evaluations show that the two (t,n)-threshold verification scheme variants always exhibit more favourable properties than the naive approach and that when deciding between the two variants, the exact application scenario must be considered. Three use cases illustrate as exemplary application scenarios the versatility of the proposed (t,n)-threshold verification scheme. By addressing the aforementioned three distinct challenges, this thesis demonstrates the breadth of the field of usable and secure user authentication ranging from awareness materials, to the assessment and evaluation of authentication schemes, to applying cryptography to craft secure password storage solutions. The research processes, results, and insights described in this thesis represent important and meaningful contributions to the state of the art in the research on usable and secure user authentication, offering benefits for users, organisations, and researchers alike

The Role of Eye Gaze in Security and Privacy Applications: Survey and Future HCI Research Directions

For the past 20 years, researchers have investigated the use of eye tracking in security applications. We present a holistic view on gaze-based security applications. In particular, we canvassed the literature and classify the utility of gaze in security applications into a) authentication, b) privacy protection, and c) gaze monitoring during security critical tasks. This allows us to chart several research directions, most importantly 1) conducting field studies of implicit and explicit gaze-based authentication due to recent advances in eye tracking, 2) research on gaze-based privacy protection and gaze monitoring in security critical tasks which are under-investigated yet very promising areas, and 3) understanding the privacy implications of pervasive eye tracking. We discuss the most promising opportunities and most pressing challenges of eye tracking for security that will shape research in gaze-based security applications for the next decade