What is CAPTCHA and How it works?

What is CAPTCHA and How it  works?

CAPTCHA stands for Completely Automated Public Turing Test to Tell Computers and Humans Apart.  It’s a commonly-used technology that checks to see if online users are, in fact, humans or if they are  software robots  (commonly referred to simply as “bots”) seeking to wreak havoc.  CAPTCHA makes this distinction by relying on specific traits that only humans possess.  

WHAT DOES CAPTCHA DO?

CAPTCHA is widely used throughout the web as a means to protect users from bots, spam and  DOS  (denial of service) attacks.  Unfortunately, there are people out there who want to harm user websites and systems for all kinds of reasons. Perhaps it’s a means to stave off competition or unwelcome advertising, or perhaps it’s simply to express destructive behavior.  Whatever the reason may be, CAPTCHA is a means to counteract these attacks, and trust us when we tell you that this is one technology that is truly doing us all a favor.   

The DOS attack we mentioned is arguably the most basic example of what CAPTCHA technologies work to fend off.  These attacks are specifically designed to make resources entirely unavailable. Those staging these attacks, send out large numbers of requests to a given server, overwhelming it, and therefore making it incapable of returning results.  It essentially blocks your website.  Now, the fundamental concept that you need to understand here, though, is that actual humans are not sending out these attacks, as it would simply be too time-consuming to send out that sort of large number of requests at one time.  Computers are doing all of the work in this scenario by sending out hundreds of requests every single second.  It is this unusual behavior that CAPTCHA helps to identify and block.