Development and Evaluation of Swahili Text Based CAPTCHA

CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) is a test used in computing to determine whether the user is human or not and can be used in websites to offer protection against malicious programs (bots) which run automated tasks such as posting fake comments. Most of the Swahili language based websites in Tanzania still use English language based CAPTCHAs such as Google's reCAPTCHA v2 which has poor usability for native Swahili users and poor robustness. This paper proposes Swahili CAPTCHA which requires users to recognize and correctly spell the distorted and misspelled Swahili words. Evaluation findings reveal that Swahili CAPTCHA is easier to learn and use and has similar robustness compared to reCAPTCHA v2.