A Review of Usage & Security of CAPTCHAs to Protect Web Resources and Web Service’s Performance
Mehul Patel, Manish I. Patel · Journal of Emerging Technologies and Innovative Research · 2017
To protect web resources and web services from computer bot program, various types of CAPTCHAs are used. In all types of CAPTCHAs, Text-Based CAPTCHA is widely used by many web service providers. In this review paper, different types, applications, security issues and features about the CAPTCHA system are discussed, including the techniques involved. As a performance parameter, the breaking ratio is summarized from various research articles.