What is a CAPTCHA

  • CAPTCHA - Completely Automated Public Turing test to tell Computers and Humans Apart
  • In olden days CAPTCHAs were overcome by paying computer sweatshops to solve them (manual human solving of bulk CAPTCHAs)
  • But computer vision has come a long way today and CAPTCHAs can be easily solved by hackers today.

Enter reCAPTCHA

  • It is the “I’m not a robot” box
  • The trick is not in clicking the box!
  • A set of parameters are used to distinguish a human from a bot,
    • The mouse movement towards the box
    • Clicking order and mouse movement when solving image based tests
    • Browsing history (yup!) - the latest reCAPTCHA versions don’t even need us to click the box

Refs

  1. https://www.youtube.com/watch?v=4UuvwY6CdLo