A Novel Arabic CAPTCHA Generation Framework Based on Pseudoisochromatic Plates for Enhanced Human Verification

This paper presents a novel Arabic CAPTCHA generation framework that leverages Pseudoisochromatic Plates (PIPs)—a technique traditionally used in color vision testing—to enhance security and usability in human verification systems. The proposed scheme embeds both printed and handwritten Arabic texts into PIP-style backgrounds using randomized color blending and non-font-based character rendering. This design introduces high visual complexity that resists segmentation and recognition by automated solvers while maintaining legibility for human users. A comprehensive experimental evaluation involving human participants and machine recognition tools demonstrates the robustness of the proposed approach against state-of-the-art attacks, including Google Vision API. Usability assessments further indicate that, while handwritten text embedded in PIP backgrounds achieves superior security, printed text offers better efficiency and effectiveness. The results underscore a critical trade-off between CAPTCHA security and usability and highlight the potential of PIP-based mechanisms to improve Arabic CAPTCHA systems. This work introduces a new direction in CAPTCHA design tailored for linguistically complex scripts and provides valuable insights for developing secure and user-inclusive verification tools in Arabic-speaking digital environments.