Implementation of captcha (Completely Automated Public Turing-Test to Tell Computers and Humans Apart) that is both easy to use and easy to customize/extend.

Death by Captcha Ruby implementation (HTTP API)

Captcha based on encyrpting and decrypting user data by mathematical operation

This version include two important page 'Contact' and 'Register' with the 'Math-Captcha' method submit for prevent hacker attack.

you will get arithmatic sum with answer you just have to compare with ur user in controller