An algorithm for automatically choosing distractors for recognition based authentication using minimal image types

<p>When a user logs on to a recognition based authentication system, he or she is presented with a number of images, one of which is their pass image and the others are distractors. The user must recognise and select their own image to enter the system. If any of the distractors is too similar to the target, the user is likely to become confused and may well choose a distractor by mistake.</p> <p>It is simple for humans to rule on image similarity but such a labour intensive approach hinders the wider uptake of these mechanisms. Automating image similarity detection is a challenging problem but somewhat easier when the images being used are minimal image types such as hand drawn doodles and Mikons constructed using a computer tool.</p> <p>We have developed an algorithm, which has been reported earlier, to automatically detect if two doodle images are similar. This paper reports a new experiment to discover the amount of similarity in collections of doodles and Mikons, from a human perspective. This information is used to improve the algorithm and confirm that it also works well with Mikons.</p&gt

Towards a metric for recognition-based graphical password security

Recognition-based graphical password (RBGP) schemes are not easily compared in terms of security. Current research uses many different measures which results in confusion as to whether RBGP schemes are secure against guessing and capture attacks. If it were possible to measure all RBGP schemes in a common way it would provide an easy comparison between them, allowing selection of the most secure design. This paper presents a discussion of potential attacks against recognition-based graphical password (RBGP) authentication schemes. As a result of this examination a preliminary measure of the security of a recognition-based scheme is presented. The security measure is a 4-tuple based on distractor selection, shoulder surfing, intersection and replay attacks. It is aimed to be an initial proposal and is designed in a way which is extensible and adjustable as further research in the area develops. Finally, an example is provided by application to the PassFaces scheme

Comparing the usability of doodle and Mikon images to be used as authenticators in graphical authentication systems

Recognition-based graphical authentication systems rely on the recognition of authenticator images by legitimate users for authentication. This paper presents the results of a study that compared doodle images and Mikon images as authenticators in recognition based graphical authentication systems taking various usability dimensions into account. The results of the usability evaluation, with 20 participants, demonstrated that users preferred Mikon to doodle images as authenticators in recognition based graphical authentication mechanisms. Furthermore, participants found it difficult to recognize doodle images during authentication as well as associate them with something meaningful. Our findings also show the need to consider the security offered by the images, especially their predictability

The effectiveness of intersection attack countermeasures for graphical passwords

Recognition-based graphical passwords are one of several proposed alternatives to alphanumerical passwords for user authentication. However, there has been limited work on the security of such schemes. Often authors state a possible attack combined with a proposed countermeasure, but the efficacy of the counter measure is not always quantitatively examined. One possible attack which has been discussed without this examination is an intersection attack. If we can establish which countermeasures for this attack are effective, this will provide insight which will make it possible to select the appropriate countermeasure for the level of security required by a given system. Our approach involved creating a simulation of intersection attacks using each of five possible counter measures. The number of attacks which had to be performed before success for each approach was noted and compared to a control where no counter measure was implemented. Our results show that for three of the five countermeasures there was a significant increase in the number of attacks before success, one showed a significant decrease and the other did not show any statistical significance. We show that it is not decisive that using dummy screens when an incorrect image is selected will increase the number of attacks required. We also show that increasing the number of challenge screens reduces the number of attacks required before success as the number of challenge screens approaches the size of the passimage set. Our results allow one to make a more reliable choice of countermeasure to reduce intersection attacks

Survey of teachers 2010 : support to improve teaching practice

In 2010 the annual survey of teachers, conducted on behalf of the General Teaching Council for England (GTC), explored teachers’ experiences of the different forms of support they receive to help them maintain and develop their teaching practice. Teachers were asked for their views on the following: • their participation in Continuing Professional Development (CPD) • their involvement in activities to improve teaching practice • use of observation and feedback • use of research • performance management, and • the professional standards

Multicriteria optimization to select images as passwords in recognition based graphical authentication systems

Usability and guessability are two conflicting criteria in assessing the suitability of an image to be used as password in the recognition based graph -ical authentication systems (RGBSs). We present the first work in this area that uses a new approach, which effectively integrates a series of techniques in order to rank images taking into account the values obtained for each of the dimen -sions of usability and guessability, from two user studies. Our approach uses fuzzy numbers to deal with non commensurable criteria and compares two multicriteria optimization methods namely, TOPSIS and VIKOR. The results suggest that VIKOR method is the most applicable to make an objective state-ment about which image type is better suited to be used as password. The paper also discusses some improvements that could be done to improve the ranking assessment

A comprehensive study of the usability of multiple graphical passwords

Recognition-based graphical authentication systems (RBGSs) using images as passwords have been proposed as one potential solution to the need for more usable authentication. The rapid increase in the technologies requiring user authentication has increased the number of passwords that users have to remember. But nearly all prior work with RBGSs has studied the usability of a single password. In this paper, we present the first published comparison of the usability of multiple graphical passwords with four different image types: Mikon, doodle, art and everyday objects (food, buildings, sports etc.). A longi-tudinal experiment was performed with 100 participants over a period of 8 weeks, to examine the usability performance of each of the image types. The re-sults of the study demonstrate that object images are most usable in the sense of being more memorable and less time-consuming to employ, Mikon images are close behind but doodle and art images are significantly inferior. The results of our study complement cognitive literature on the picture superiority effect, vis-ual search process and nameability of visually complex images

\u3ci\u3eIn Sacred Time\u3c/i\u3e

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