Towards A Universally Usable Human Interaction Proof: Evaluation of Task Completion Strategies

摘要

The need for security features to stop spam and bots has prompted research aimed at developing human interaction proofs (HIPs) that are both secure and easy to use. The primarily visual techniques used in these HIP tools present difficulties for users with visual impairments. This article reports on the development of Human-Interaction Proof, Universally Usable (HIPUU), a new approach to human-interaction proofs based on identification of a series of sound/image pairs. Simultaneous presentation of a single, unified task in two alternative modalities provides multiple paths to successful task completion. We present two alternative task completion strategies, based on differing input strategies (menu-based vs. free text entry). Empirical results from studies involving both blind and sighted users validate both the usability and accessibility of these differing strategies, with blind users achieving successful task completion rates above 90%. The strengths of the alternate task completion strategies are discussed, along with possible approaches for improving the robustness of HIPUU.