Why Does Everything Have CAPTCHA These Days?

Why Does Everything Have CAPTCHA These Days?

You have definitely come across CAPTCHA countless times even without knowing its name. Let’s get into it real quick for those who don’t know what CAPTCHA is. CAPTCHA is a challenge-response system that distinguishes between robots and humans using a website where you have to “prove you’re human”. CAPTCHA, which stands for Completely Automated Public Turing Test to tell Computers and Humans Apart, has become increasingly popular on various websites to decrease spam and prove the legitimacy of its users.

Image showing car and traffic lights used for authentication

Image showing car and traffic lights used for authentication

CAPTCHAs are used as security tests to prevent spammers and hackers from inserting dangerous or frivolous code into online forms. Users often encounter CAPTCHA and reCAPTCHA tests on the Internet. The first known spam email was sent in 1978. Almost five decades later, email spam continues to plague us. Many years of engineering effort have been put into defeating it, and yet spam persists. There are billion-dollar industries on both sides, i.e. those defending against it and those sending it.
Why is this? The answer is simple. So long as there is an incentive to abuse a system, someone will generally find a way. And once they do, someone else will now have an incentive to stop them. This behavior simply reflects fundamental human nature, and five thousand years of recorded history imply the dynamic is unlikely to change any time soon.
Just as there will always be people who want to get your attention via email, there will always be the desire to constrain access to some resources such that only humans can access them.
Whether the goal is to prevent:

  • preventing blog comment spam
  • Keeping website registration safe
  • Defending against dictionary hacks by protecting the password system

among many other uses, being able to filter online traffic on the basis of “human or not” will likely remain a valuable tool so long as human nature follows the same patterns recorded over the last five thousand years.