Alain Forget

Multiple password interference in text passwords and click-based graphical passwords

The underlying issues relating to the usability and security of multiple passwords are largely unexplored. However, we know that people generally have difficulty remembering multiple passwords. This reduces security since users reuse the same password for different systems or reveal other passwords as they try to log in. We report on a laboratory study comparing recall of multiple text passwords with recall of multiple click-based graphical passwords. In a one-hour session (short-term), we found that participants in the graphical password condition coped significantly better than those in the text password condition. In particular, they made fewer errors when recalling their passwords, did not resort to creating passwords directly related to account names, and did not use similar passwords across multiple accounts. After two weeks, participants in the two conditions had recall success rates that were not statistically different from each other, but those with text passwords made more recall errors than participants with graphical passwords. In our study, click-based graphical passwords were significantly less susceptible to multiple password interference in the short-term, while having comparable usability to text passwords in most other respects.

Persuasive Cued Click-Points: Design, Implementation, and Evaluation of a Knowledge-Based Authentication Mechanism

This paper presents an integrated evaluation of the Persuasive Cued Click-Points graphical password scheme, including usability and security evaluations, and implementation considerations. An important usability goal for knowledge-based authentication systems is to support users in selecting passwords of higher security, in the sense of being from an expanded effective security space. We use persuasion to influence user choice in click-based graphical passwords, encouraging users to select more random, and hence more difficult to guess, click-points.

User interface design affects security: patterns in click-based graphical passwords

Design of the user interface for authentication systems influences users and may encourage either secure or insecure behaviour. Using data from four different but closely related click-based graphical password studies, we show that user-selected passwords vary considerably in their predictability. Our post-hoc analysis looks at click-point patterns within passwords and shows that PassPoints passwords follow distinct patterns. Our analysis shows that many patterns appear across a range of images, thus motivating attacks which are independent of specific background images. Conversely, Cued Click-Points (CCP) and Persuasive Cued Click-Points (PCCP) passwords are nearly indistinguishable from those of a randomly generated simulated dataset. These results provide insight on modeling effective password spaces and on how user interface characteristics lead to more (or less) security resulting from user behaviour.

Shoulder-surfing resistance with eye-gaze entry in cued-recall graphical passwords

We present Cued Gaze-Points (CGP) as a shoulder-surfing resistant cued-recall graphical password scheme where users gaze instead of mouse-click. This approach has several advantages over similar eye-gaze systems, including a larger password space and its cued-recall nature that can help users remember multiple distinct passwords. Our 45-participant lab study is the first evaluation of gaze-based password entry via user-selected points on images. CGPs usability is potentially acceptable, warranting further refinement and study.

Exploring usability effects of increasing security in click-based graphical passwords

Graphical passwords have been proposed to address known problems with traditional text passwords. For example, memorable user-chosen text passwords are predictable, but random system-assigned passwords are difficult to remember. We explore the usability effects of modifying system parameters to increase the security of a click-based graphical password system. Generally, usability tests for graphical passwords have used configurations resulting in password spaces smaller than that of common text passwords. Our two-part lab study compares the effects of varying the number of click-points and the image size, including when different configurations provide comparable password spaces. For comparable spaces, no usability advantage was evident between more click-points, or a larger image. This is contrary to our expectation that larger image size (with fewer click-points) might offer usability advantages over more click-points (with correspondingly smaller images). The results suggest promising opportunities for better matching graphical password system configurations to device constraints, or capabilities of individual users, without degrading usability. For example, more click-points could be used on smart-phone displays where larger image sizes are not possible.

Persuasion for Stronger Passwords: Motivation and Pilot Study

Text passwords are the ubiquitous method of authentication, used by most people for most online services. Many people choose weak passwords that are vulnerable to attackers who simply guess all the passwords within the most probable password spaces. This paper describes a lightweight password creation mechanism that uses Persuasive Technology to influence users to create stronger passwords. Results from a pilot study show that our Persuasive Text Passwords (PTP) prototype system successfully influenced users to create and remember more secure passwords.

Helping users create better passwords: is this the right approach?

Users tend to form their own mental models of good passwords regardless of any instructions provided. They also tend to favour memorability over security. In our study comparing two mnemonic phrase-based password schemes, we found a surprising number of participants misused both schemes. Intentional or not, they misused the system such that their task of password creation and memorization became easier. Thus, we believe that instead of better instructions or password schemes, a new approach is required to convince users to create more secure passwords. One possibility may lie in employing Persuasive Technology.

A Spoonful of Sugar?: The Impact of Guidance and Feedback on Password-Creation Behavior

Users often struggle to create passwords under strict requirements. To make this process easier, some providers present real-time feedback during password creation, indicating which requirements are not yet met. Other providers guide users through a multi-step password-creation process. Our 6,435-participant online study examines how feedback and guidance affect password security and usability. We find that real-time password-creation feedback can help users create strong passwords with fewer errors. We also find that although guiding participants through a three-step password-creation process can make creation easier, it may result in weaker passwords. Our results suggest that service providers should present password requirements with feedback to increase usability. However, the presentation of feedback and guidance must be carefully considered, since identical requirements can have different security and usability effects depending on presentation.

The MVP Web-Based Authentication Framework

MVP is a framework allowing websites to use diverse knowledge-based authentication schemes. One application is its use in conducting ecologically valid user studies of authentication under the same experimental conditions. We introduce MVP and its key characteristics, discuss several authentication schemes, and offer lessons learned from running 9 hybrid (lab/online) and 3 MTurk user studies over the last year.

Memorability of persuasive passwords

Text passwords are the primary authentication method used for most online services. Many online users select weak passwords. Regrettably, most proposed methods of strengthening passwords compromise memorability. This paper explores a lightweight password creation mechanisms effect on password memorability. Our system employs Persuasive Technology to assist users in creating stronger passwords. Results show that our improvement scheme affected password memorability only for users who created secure passwords before the system applied its improvement. This result warns researchers to not alienate users who are already security-aware when trying to assist security-unaware users to behave more securely.