Karen Renaud

Is a picture really worth a thousand words? Exploring the feasibility of graphical authentication systems

The weakness of knowledge-based authentication systems, such as passwords and Personal Identification Numbers (PINs), is well known, and reflects an uneasy compromise between security and human memory constraints. Research has been undertaken for some years now into the feasibility of graphical authentication mechanisms in the hope that these will provide a more secure and memorable alternative. The graphical approach substitutes the exact recall of alphanumeric codes with the recognition of previously learnt pictures, a skill at which humans are remarkably proficient. So far, little attention has been devoted to usability, and initial research has failed to conclusively establish significant memory improvement. This paper reports two user studies comparing several implementations of the graphical approach with PINs. Results demonstrate that pictures can be a solution to some problems relating to traditional knowledge-based authentication but that they are not a simple panacea, since a poor design can eliminate the picture superiority effect in memory. The paper concludes by discussing the potential of the graphical approach and providing guidelines for developers contemplating using these mechanisms.

Predicting technology acceptance and adoption by the elderly: a qualitative study

Technology adoption has been studied from a variety of perspectives. Information systems, Sociology and Human-Computer Interaction researchers have come up with various models incorporating factors and phases to predict adoption that, in turn, will lead to persistent use. Technology acceptance by the elderly mobile phone user has received less attention and no model currently exists to predict factors influencing their technology adoption. A literature study yielded a set of acceptance factors (derived mostly from quantitative studies) and adoption phases (derived mostly from qualitative studies) that could influence and predict mobile phone adoption by the elderly user. We confirmed a subset of these factors by consulting findings from research into the context of senior mobile phone users, including the needs and limitations of these users. We then verified the factors qualitatively by means of structured interviews with senior mobile phone users. The interviews included the use of scenarios as well as a mobile phone design activity. Triangulating the quantitative findings from literature with the qualitative findings from this study led to a set of interlinked acceptance factors and adoption phases that we present as the Senior Technology Acceptance& Adoption model for Mobile technology (STAM). This paper makes a contribution to understanding technology acceptance by senior users and should be of interest to researchers, designers and decision-makers on technology adoption, especially mobile features and services.

On user involvement in production of images used in visual authentication

Recognition-based visual authentication schemes use a variety of different kinds of images. These mechanisms have now matured sufficiently that we should start considering tailoring and fine-tuning them-looking at ways to make them more efficient. Since these mechanisms use images, the obvious starting point in this tailoring process is to consider the image type or genre being used by the mechanism. Images have a number of properties which are bound to influence the efficacy of the visual authentication mechanism. In this paper the notion of essential and tuning image properties is proposed. The former are those that an image must exhibit or possess in order to be used in visual authentication at all-failure to meet these metrics should disqualify the image from use. Tuning properties, on the other hand, are properties that will improve the efficiency of the mechanism. The tuning property which is the focus of this paper is the users involvement in the production of his/her secret images. A longitudinal study was carried out with a visual authentication system in order to determine the effectivity of images with three levels of user involvement, using randomly issued images from an archive, a set of hand-drawn images called doodles, and user-provided photos. The hand-drawn doodles performed better than both system-issued images and personal photos. Furthermore, whereas doodles demonstrate viability, personal photos have many insuperable problems which make them unsuitable for use in a security setting.

A Qualitative Study of the Applicability of Technology Acceptance Models to Senior Mobile Phone Users

This paper investigates the factors that influence mobile phone adoption by the older user. Technology adoption is a process, with the adopter progressing from a state of ignorance of the technology to embracing it and considering it a necessity. Full progression can only occur if the adopter fully acceptsthe technology. If not, he or she is unlikely to progress towards wholehearted adoption and remain a reluctant user or discard the technology altogether. Many theoretical models explain the dynamics of technology acceptance by proposing particular predictive factors and are based on quantitative studies built on the responses of students or economically active adults. This begs the question: Do existing technology acceptance models incorporate the factors that lead to mobile phone adoption and use by older adults? We consulted findings from studies of senior mobile phone users and extracted a number of issues concerning needs, uses and limitations, which we verified by means of structured interviews with senior mobile phone users. We compare these qualitatively derived issues with the factors from existing quantitative models. This led to the identification of a two-dimensional adoption matrix where verified acceptance factors, derived from the experiences and opinions of our participants, are mapped against a recognised adoption process, highlighting the fact that current models only partly predict adoption and acceptance by the senior mobile phone user.

My password is here! An investigation into visuo-spatial authentication mechanisms

Abstract Passwords are the almost universal authentication mechanism, even though they are basically flawed and cause problems for users due to poor memorability. Graphical methods of authentication have recently excited some interest but little is known about their actual efficacy. There are basically two types of graphical authentication mechanisms: recognition-based and location-based—also called visuo-spatial mechanisms. Whereas some kinds of recognition-based graphical authentication mechanisms have been evaluated by various researchers, there is still a need to investigate location-based graphical authentication mechanisms in a more rigorous fashion to determine whether they could be a viable alternative to traditional passwords for web usage. This paper discusses graphical authentication mechanisms in general and reports on the evaluation of one particular visuo-spatial mechanism, aimed at augmenting the password paradigm by providing a way to record passwords securely. Results and findings are presented, and conclusions drawn, some of which can also be applied to other types of visuo-spatial mechanisms. We also propose a set of metrics which can be used to measure the quality of web authentication mechanisms and apply these to a range of existing authentication mechanisms.

Don't do this - Pitfalls in using anti-patterns in teaching human-computer interaction principles

This paper explores the use of design patterns and anti-patterns in teaching human-computer interaction principles. Patterns are increasingly popular and are seen as an efficient knowledge transfer mechanism in many fields, including software development in the field of software engineering, and more recently in the field of human-computer interaction. In software engineering a concerted effort is also being made to identify and document anti-patterns for recording the experiences of expert software developers to caution novices against potential bad practices. It is, however, essential that we ensure compatibility with the learners internal knowledge representation and acquisition processes, whether we are attempting to convey the knowledge in the form of a pattern or an anti-pattern. Since teaching with anti-patterns implies using negation, the primary aim of the research reported in this paper is to explore the efficacy of negative, rather than positive, teaching mechanisms. Evidence from theories of mental modelling and knowledge acquisition that highlight significant dangers in the use of anti-patterns to teach novices human-computer interaction principles is presented and supported with empirical findings. We started off by investigating the use of patterns (positive) in teaching, and then carried out experiments to test the use of anti-patterns (negative) in teaching HCI principles. This paper, whilst reporting mainly on our findings with respect to HCI design anti-patterns, will also identify some problems with the structure and use of patterns and anti-patterns in pedagogy.

Why Doesn’t Jane Protect Her Privacy?

End-to-end encryption has been heralded by privacy and security researchers as an effective defence against dragnet surveillance, but there is no evidence of widespread end-user uptake. We argue that the non-adoption of end-to-end encryption might not be entirely due to usability issues identified by Whitten and Tygar in their seminal paper “Why Johnny Can’t Encrypt”. Our investigation revealed a number of fundamental issues such as incomplete threat models, misaligned incentives, and a general absence of understanding of the email architecture. From our data and related research literature we found evidence of a number of potential explanations for the low uptake of end-to-end encryption. This suggests that merely increasing the availability and usability of encryption functionality in email clients will not automatically encourage increased deployment by email users. We shall have to focus, first, on building comprehensive end-user mental models related to email, and email security. We conclude by suggesting directions for future research.

Guidelines for designing graphical authentication mechanism interfaces

The password era is drawing to a close. The latest technology is being released without keyboards, which makes password entry insecure and arduous. Furthermore, everyone is straining under the burden of multiple passwords and Personal Identification Numbers (PINs), and a viable knowledge-based alternative is urgently required. In the last few years a number of innovative graphical authentication mechanisms, which use pictures instead of alphanumeric strings, have been proposed. There is long-standing evidence that people remember pictures far better than they remember alphanumeric strings, so in terms of easing the memory load, pictures seem to offer a viable alternative. However, what is emerging from current research is that the design of such a graphical authentication mechanism interface can either make or break it, both in terms of security and usability. This paper will discuss various design options and make recommendations about how such systems should be designed in order to make them maximally efficacious while considering the level of risk associated with the resource being protected by the mechanism.

DynaHand: Observation-resistant recognition-based web authentication

Authentication in a Web environment is severely constrained by a minimal expectation of an infrastructure made up of software, hardware, and operator expertise. The traditional mechanism, passwords, is outliving its usefulness in the Web arena. This article presents results from a field test of a graphical authentication system called DynaHand, which utilizes biometrics, i.e. human handwriting recognition, in a graphical authentication mechanism. We also present a tool that supports the analysis of errors evidenced during the authentication process, making it possible to classify failed attempts as either due to genuine user error or failed intrusions. In the case of the former, the tool helps to reduce the occurrence of such genuine errors by identifying distractor images that could potentially cause confusion due to their similarity to target images.

Worth-centred mobile phone design for older users

The twenty-first century society fights against an inherent tendency to over-classify and label people. In the case of the aged, despite all efforts, the perception of the helpless, feeble older person still prevails. The truth of the matter is that people over sixty often do not fit this profile. The aged are a heterogeneous group with varying different skills and abilities in many different areas. This paper challenges prevalent mobile phone design decisions that appear to have been made based on the erroneous pre-conception of the incapable elder. Designers currently produce “senior” mobile phones that are, at best, inadequate and, at worst, insulting to a sector of society that deserves respect and consideration. Age does indeed influence mobile phone usage, and people over sixty often have specific and special needs, quite apart from age-related limitations, that predict their use of mobile phones. Most mobile phones designed for older users simply reduce the number of features: the so-called simplification approach. Apart from reducing the effectiveness of the phone, this approach often incorporates the fatal design flaw of using numbers or letters, on speed-dial buttons, which requires the user to remember the button–person mappings. In fact, this design rationale reduces the value of the phone to the user. This paper argues that mobile phone design for older users should be worth-centred (Cockton G in Designing worth is worth designing. In: Proceedings of the 4th Nordic conference on human–computer interaction: changing roles. Oslo, Norway, pp 165–174, 2006) rather than simplification-driven. The worth-centred approach maximises worth to the user of the phone. This is achieved by maximising effectiveness while accommodating reduced capabilities. To maximise ease of use, and consequent accessibility, features may have to be reduced in an informed way. To facilitate this, a mapping process is proposed whereby user needs are linked to uses of the phone, and then to the features that facilitate these uses. Needs fall into a number of categories, and each category is characterised by a number of different uses, which form a usage space. Features can be linked to one or more usage spaces, and thus be used to support needs. The first step in the conducted research entailed the identification of the needs of the older mobile phone user. Then, it was determined whether these needs were indeed being met by the uses afforded in existing phones. Having concluded that most users’ needs were not being met, the next step was to capture data on the needs, limitations and expectations of people over the age of sixty. This was achieved by conducting a series of one-to-one interviews with a number of older mobile phone users and also supervising a participatory design experiment. Using the findings of the analysis, a usage space model is proposed, which serves to align feature inclusion with user needs. Based on this usage space model (the theoretical contribution), a prototype mobile phone design is presented as the practical contribution of the paper.