Accessible privacy and security: a universally usable human-interaction proof tool

Despite growing interest in designing usable systems for managing privacy and security, recent efforts have generally failed to address the needs of users with disabilities. As security and privacy tools often rely upon subtle visual cues or other potentially inaccessible indicators, users with perceptual limitations might find such tools particularly challenging. To understand the needs of an important group of users with disabilities, a focus group was conducted with blind users to determine their perceptions of security-related challenges. Human-interaction proof (HIP) tools, commonly known as CAPTCHAs, are used by web pages to defeat robots and were identified in the focus group as a major concern. Therefore, a usability test was conducted to see how well blind users were able to use audio equivalents of these graphical tools. Finally, an accessible HIP tool was developed which combines audio and matching images, supporting both visual and audio output. Encouraging results from a small usability evaluation of the prototype with five sighted users and five blind users show that this new form of HIP is preferred by both blind and visual users to previous forms of text-based HIPs. Future directions for research are also discussed.