• CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart)
  • Used to authenticate user input
  • Consists of randomly generated image with distorted letters/numbers
  • Determines whether the input is given by a real user or a computer program
  • Used to mitigate attacks caused by automated tools
  • Implemented on applications using third party software like jcaptcha, simplecaptcha, recaptcha

Sample Code for Creating CAPTCHA

Sample Code for Creating CAPTCHA (Cont’d)

Sample Code for CAPTCHA Verification

Sample Code for Displaying CAPTCHA

The CAPTCHA is displayed using JSP

index.jsp

result.jsp