What is CAPTCHA and How is it Used?

by in Uncategorized

Tags: CaptchaSecurity

Have you ever wondered what those crazy letters are? Or why you’re required to type them into the box?

CAPTCHA: What it stands for and where it came from:

The term CAPTCHA stands for Completely Automated Public Turing Test To Tell Computers and Humans Apart and was coined in 2000 by Luis von Ahn, Manuel Blum, Nicholas Hopper and John Langford of Carnegie Mellon University.

A CAPTCHA is a program that protects websites or other applications against computer bots by generating and grading tests that humans can pass, but current computer programs cannot. For example, humans can read distorted text as it’s shown on the image, but current computer programs can’t.

In other words, the reason websites have CAPTCHA is spam!

If you have ever tried to register with a website or comment on a blog and been asked to enter some crazy letters that have been all jumbled up, you know how frustrating it can sometimes be to tell an L from a 1 or a J from an I. I know, I’ve been there and aslo get frustrated when miss it couple of times.

But let’s not to forget that the only reason we see CAPTCHAs is because of enormous amount of spam these days. So, next time you run up against one of those images and get a little frustrated trying to tell a Q from an O, just remember not to vent your frustration at the website. Focus it on the spammers, because they are the reason we have to stare at your screen almost every time we want to register at a new website.

Different types of CAPTACHA include (but are not limited to):

  • Text recognition based (example: reCAPTCHA)
  • Image recognition based (example: identiPIC)
  • Social Authentication/ Friend Recognition (example: facebook CAPTCHA)
  • Logic questions based (example: textCAPTCHA)
  • User interaction (example: sliders type)
  • Honeypot

Keep an eye out for my next post about how to determine the effectiveness of your CAPTCHA.