Captcha Form Protection
What is Captcha? Captcha is a backronym for “Completely Automated Public Turing test to tell Computers and Humans Apart”. It is is a type of challenge-response test used in computing to determine whether or not the user is human. The purpose of Captcha is to deter hackers, spammers, etc. from using software to auto-submit forms. For example, to spam message boards, blogs, etc. The person is presented with a challenge to which the person must respond correctly. For example, in its earliest and simplest implementation, a graphic is displayed which contains a random selection of letters and numbers. The person must type the same characters into a box before they can submit the form.
There are almost as many Captcha algorithms out there as they are combinations and permutations of letters and numbers. No shortage indeed. Some better than others. The old style of Captcha in which the surfer is presented with a random sequence of letters and/or numbers is rather old school. And frankly, outdated and obsolete. There are a number of OCR (optical character recognition) software out there which can read these, and auto-submit the form. Attempts have been made to obscure the Captchas by using distortion algorithms. But, they are largely ineffective. There are Flash-based Captchas, but most mobile devices (including iPhone and Android phones) will not render Flash. The better mousetrap are Captchas that challenge the surfer to perform a graphic-based action. Moving objects, selecting objects, etc. These are highly effective. There are many of these available. But one stands out.
The one that stands out is Google’s reCAPCTHA. This one works really, really well. And, it is user-friendly. The older text-graphic-based Captchas (including the older reCAPTCHA) got too complicated and difficult for surfers due to the distortions used. Often not accessible for visually impaired individuals. reCAPTCHA gets around this. Strongest and more secure method of Captcha out there, while being very easy to use.
We use reCAPTCHA extensively site-wide on out site for all forms and our Blog. It works so well that we have had no problems with form spamming. So, it is the Captcha he highly recommend to everyone and to all of our clients. As a matter of fact, we are looking at replacing our existing Captcha system used by our Password Sentry PHP Authentication Plugin with reCAPTCHA.
Nevertheless, regardless of which Captcha you use, just make sure you use one. Protect your forms (contact forms, message boards, blogs, etc.) from spammers and hackers. Captcha form protection has never been more important.