Results tagged “captchas” from Appleseed Blog

I recently finished a project for a client that involved installing CAPTCHAs on their various web forms. You've seen these before - they're the little widgets that challenge you to retype the intentionally garbled numbers and letters it displays in order to prove that you're an actual human, and not a node of some spammer's botnet.

In researching the current best practices for adding a CAPTCHA to an existing site, I found ReCAPTCHA, a project of Carnegie Mellon University. You've probably come across examples of this particular flavor of CAPTCHA before. The image always consists of two unrelated words or word fragments, usually resembling smudgily typed copy with some additional bot-foiling visual artifacts thrown on for good measure. Something like this:

It happens that the two words have a very good reason for looking like they do: they have been scanned out of old printed books and periodicals, part of various CMU-affiliated efforts to digitize old media. As ReCAPTCHA's own About page explains, even the best OCR software is only so-so at recognizing text, and frequently can't recognize words that would be obvious to any human reader of the language at hand.

Now, here's the cool part: by plugging itself into ReCAPTCHA, a computer working in one of these massive scanning projects can submit a word it's unsure about to the global community of people who happen to be filling web-based forms in at that very moment. It will quickly get a response that 98 percent of all the people who saw it thought the word was "doggy" (or whatnot), and that will be enough agreement for the machine's purposes.

The reason there are two words per ReCAPTCHA instance is that one of the words is undergoing this kind of trial, while the other one already has - in other words, the ReCAPTCHA system already knows what word it is. This is how the widget still functions as a CAPTCHA - the entity filling it in must still be correct about at least one of the words, if it wants to prove that it's a human. Meanwhile, bots are foiled not just for the usual reasons, but because all the words on display have already proven to be confusing to computers trying to read them!

I think this is incredibly cool. That slimy spammers have made technologies like CAPTCHAs a necessity of the modern web is quite unfortunate, but the way that ReCAPTCHA has found a way to put a positive, culture-perserving spin on it is ingenious and laudable.