Tunable Ultraviolet Vertically-emitting Organic Laser

International audienceA solid-state organic thin-film laser with intracavity frequency doubling is reported. Tunable ultraviolet emission from 309 to 322 nm is achieved from a vertical external cavity surface-emitting organic laser, with 2 % efficiency (1 µJ at 315 nm). The laser comprises a polymethyl(methacrylate) layer doped with Rhodamine 640, spun-cast onto a plane mirror, a remote concave mirror, a nonlinear crystal and a dichroic separator. The output is spectrally narrow (<0.5 nm FWHM) and tunable through phase-matching selection of the fundamental radiation lasing modes. These results highlight a low-cost and portable alternative to tunable UV laser sources, useful for spectroscopic applications

Influencing users towards better passwords: Persuasive cued click-points

Usable security has unique usability challenges because the need for security often means that standard human-computerinteraction approaches cannot be directly applied. An important usability goal for authentication systems is to support users in selecting better passwords, thus increasing security by expanding the effective password space. In click-based graphical passwords, poorly chosen passwords lead to the emergence of hotspots ' portions of the image where users are more likely to select click-points, allowing attackers to mount more successful dictionary attacks. We use persuasion to influence user choice in click-based graphical passwords, encouraging users to select more random, and hence more secure, click-points. Our approach is to introduce persuasion to the Cued Click-Points graphical password scheme (Chiasson, van Oorschot, Biddle, 2007). Our resulting scheme significantly reduces hotspots while still maintaining its usability

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

How Anesthetic, Analgesic and Other Non-Surgical Techniques During Cancer Surgery Might Affect Postoperative Oncologic Outcomes:A Summary of Current State of Evidence

The question of whether anesthetic, analgesic or other perioperative intervention during cancer resection surgery might influence long-term oncologic outcomes has generated much attention over the past 13 years. A wealth of experimental and observational clinical data have been published, but the results of prospective, randomized clinical trials are awaited. The European Union supports a pan-European network of researchers, clinicians and industry partners engaged in this question (COST Action 15204: Euro-Periscope). In this narrative review, members of the Euro-Periscope network briefly summarize the current state of evidence pertaining to the potential effects of the most commonly deployed anesthetic and analgesic techniques and other non-surgical interventions during cancer resection surgery on tumor recurrence or metastasis

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 mechanism's 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

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. CGP's usability is potentially acceptable, warranting further refinement and study

Lessons from brain age on password memorability

User authentication involves establishing a user's right to access a system. Most user authentication is done with text passwords, which have advantages over other approaches, but more secure passwords are often diffcult to remember. Nintendo's Brain Age games involve cognitive training which can improve memory. We examined Brain Age in search of insights towards helping users create and remember more secure passwords. Although Brain Age offers no techniques for memorising specific information, we discovered ideas for a new type of serious game that may help with password memorisation: Password Rehearsal Games. Copyright 2008 ACM

User-centred authentication feature framework

Purpose - This paper aims to propose that more useful novel schemes could develop from a more principled examination and application of promising authentication features. Text passwords persist despite several decades of evidence of their security and usability challenges. It seems extremely unlikely that a single scheme will globally replace text passwords, suggesting that a diverse ecosystem of multiple authentication schemes designed for specific environments is needed. Authentication scheme research has thus far proceeded in an unstructured manner. Design/methodology/approach - This paper presents the User-Centred Authentication Feature Framework, a conceptual framework that classifies the various features that knowledge-based authentication schemes may support. This framework can used by researchers when designing, comparing and innovating authentication schemes, as well as administrators and users, who can use the framework to identify desirable features in schemes available for selection. Findings - This paper illustrates how the framework can be used by demonstrating its applicability to several authentication schemes, and by briefly discussing the development and user testing of two framework-inspired schemes: Persuasive Text Passwords and Cued Gaze-Points. Originality/value - This framework is intended to support the increasingly diverse ecosystem of authentication schemes by providing authentication researchers, professionals and users with the increased ability to design, develop and select authentication schemes better suited for particular applications, environments and contexts

Guessing click-based graphical passwords by eye tracking

Click-based graphical passwords are a new method of authentication where passwords are created and entered by clicking in particular places on an image. This paper presents a study that investigated eye tracking as a potential threat to the security of such passwords. If the gaze data from people looking at an image resembles the click-points of other people's passwords, then covert eye tracking might be used to create dictionaries to effectively guess passwords. The study used an eye tracker to record the participants' gaze as they looked at images that had been used as the basis for passwords in an earlier study. We then compared the eye tracker data with the actual password click-points gathered during the earlier study, and conducted several forms of analysis to determine the likely success of guessing passwords. The eye tracker data did somewhat resemble the password click-points, and might offer attackers an advantage over guessing at random. The effectiveness shown for this approach was limited, however, although might allow improvement that would result in greater danger, especially if gaze data could be gathered without explicit interaction