How Captcha Works and Why It’s So Important

 In IT Security

You’ll be hard pressed to find an internet user in 2017 who has not encountered  CAPTCHA  at one time or another; though, you probably didn’t really know what to call it.  If you’re looking for a more long-winded name for it, 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.  


Where did CAPTCHA come from?  

The concept first came about when someone posed a question as to whether or not computers are capable of thinking on a human level; this happened around the beginning of the twentieth century as modern technologies began to establish their foothold.  It was then that an imitation game was first tested.  In this game, an interrogator had to figure out which participant was human and which was a machine. To do this, a series of questions was asked, and both had to respond.  Thus, our modern challenges were recognized.  

Today, CAPTCHA technologies are just as simple, but they are a powerful solution, nonetheless, to a very complex issue.  When you visit a website, a window may pop up asking you to enter some data or perform an action.  You then confirm it by passing a CAPTCHA test.  The one most of us are familiar with are those windows that pop up asking us to type in a combination of letters and/or numbers that we see on screen, and they’re usually slightly awkward in appearance or distorted.  Well, this appearance is because computers and bots aren’t able to recognize the distorted words, numbers or letters.  Only human eyes and brains can interpret these jumbles, because computers aren’t able to think abstractly.  Humans are incredibly sophisticated when it comes to processing visual data, where computers lack these skills entirely only possessing the capabilities to interpret zeros and ones.    

That is why these CAPTCHA technologies are so important.  They create hugely significant barriers between us and those looking to cause mayhem.  They are so simple and take very little time away from the user but accomplish great feats with just simple algorithms.  Just think.  Without these technologies in place, humans, computers and bots would have the power to just take over, sending constant attacks on users’ systems, websites, and the entire  “Internet of Things”!   So, next time a CAPTCHA screen pops up on your computer, don’t be annoyed by that little extra step; it’s there for your benefit.

Are you ready to add CAPTCHA to your website’s security arsenal? If so, our team can help, and we’ll offer additional suggestions for keeping your website and your visitors safe.

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