Antonella De Angeli

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.

Trust in online advice

Many people are now influenced by the information and advice they find on the Internet, much of it of dubious quality. This article describes two studies concerned with those factors capable of influencing peoples response to online advice. The first study is a qualitative account of a group of house-hunters attempting to find worthwhile information online. The second study describes a survey of more than 2,500 people who had actively sought advice over the Internet. A framework for understanding trust in online advice is proposed in which first impressions are distinguished from more detailed evaluations. Good web design can influence the first process, but three key factors--source credibility, personalization, and predictability--are shown to predict whether people actually follow the advice given.

Explore! possibilities and challenges of mobile learning

This paper reports the experimental studies we have performed to evaluate Explore!, an m-learning system that supports middle school students during a visit to an archaeological park. It exploits a learning technique called excursion-game, whose aim is to help students to acquire historical notions while playing and to make archaeological visits more effective and exciting. In order to understand the potentials and limitations of Explore!, our studies compare the experience of playing the excursion-game with and without technological support. The design and evaluation of Explore! have provided knowledge on the advantages and pitfalls of m-learning that may be instrumental in informing the current debate on e-learning.

Usability and biometric verification at the ATM interface

This paper describes some of the consumer-driven usability research conducted by NCR Self Service Strategic Solutions in the development of an understanding of usability and user acceptance of leading-edge biometrics verification techniques. We discuss biometric techniques in general and focus upon the usability phases and issues, associated with iris verification technology at the Automated Teller Machine (ATM) user interface. The paper concludes with a review of some of the major research issues encountered, and an outline of future work in the area.

VIP: a visual approach to user authentication

This paper addresses knowledge-based authentication systems in self-service technology, presenting the design and evaluation of the Visual Identification Protocol (VIP). The basic idea behind it is to use pictures instead of numbers as a means for user authentication. Three different authentication systems based on images and visual memory were designed and compared with the traditional Personal Identification Number (PIN) approach in a longitudinal study involving 61 users. The experiment addressed performance criteria and subjective evaluation. The study and associated design exploration revealed important knowledge about users, their attitudes towards and behaviour with novel authentication approaches using images. VIP was found to provide a promising and easy-to-use alternative to the PIN. The visual code is easier to remember, preferred by users and potentially more secure than the numeric code. Results also provided guidelines to help designers make the best use of the natural power of visual memory in security solutions.

Personalisation and trust: a reciprocal relationship?

Trust and personalisation are related constructs. Trust is generally accepted as a prerequisite for good personalisation practice. Customers are not likely to reveal confidential information about themselves to an untrustworthy party, and they may be suspicious of data harvesting practices if they feel the information may be misused in some way. But the converse relationship might also hold: good personalisation practice may be a pre-requisite for trust building online. At present, relatively few studies of trust suggest an important role for personalisation in the formation of trust, but we argue below that personalisation may play a larger role than that suggested by the current trust literature. Following a critical review of online trust studies, we suggest that personalisation is important for the development of trust in long-term relationships between consumer and online vendor, but argue that its role in short-term interactions is unclear. We then present a study that explores the extent to which people may be influenced by the promise of a personalised transaction, in order to clarify the influence of personalised practices on initial trust judgments. Most researchers agree that trust is a vital construct for e-commerce. It has been argued that in order to develop a successful e-commerce business:

A user-centered approach to user modeling

Generally, user modeling concerns a person interacting with a standing console. This scenario does not represent the Hyper Audio system in use: a visitor freely moves in a museum, gathering information from an adaptive and portable electronic guide. To provide designers with presumptive user behavior, data about visitor profiles and visit styles were collected through a questionnaire. The study pointed out unpredicted situations (e.g., the importance of social context) and confirmed some working hypotheses (e.g., the relevance of visit span). This paper reports on this experience, describing how to go from designer questions to guidelines for user modeling, making the best use of empirical data.

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.

Service Composition for Non-programmers: Prospects, Problems, and Design Recommendations

Although Service Oriented Architecture technologies are becoming widespread, user research to support the exploitation and composition of services by non-programmers is still in its infancy. This paper presents three user studies conducted during the user-centered design of the Serv Face Builder, a service composition tool for non-programmers. Results suggest that end users do not realize that services can be connected together and do not easily understand that information can flow between services. Further conceptual and usability problems of service composition for end users and some guidelines to overcome them are discussed.

Assessing interaction styles in web user interfaces

An evaluation of two websites with the same content but different interface styles (traditional menu-based and interactive metaphors) is described. A formative usability evaluation was carried out with heuristic assessment of aesthetics followed by post-test memory. The subjects had more problems with the metaphor-based site, but rated it more favourably on the aesthetics heuristics. There was no difference in free memory recall between the sites. The implications for website design and evaluation are discussed.