reCAPTCHA accepting one word out of two

captcha recaptcha
user393580 picture user393580 · Jul 22, 2010 · Viewed 8.1k times · Source

I am a bit confused about how reCAPTCHA works. I have implemented it using ROR.

Sometimes even if i specify only one word out of two, it returns true while sometimes it fails.

I am really confused and not able to understand the behaviour of reCAPTCHA.

Answer

Rex M picture Rex M · Jul 22, 2010

Only one of the recaptcha words is "known" by the system - it is relying on the user performing the captcha to tell the system what the other word is, because it is not machine-readable.

That is the "point" of recaptcha, or the added benefit - it is not only performing a human test, it is also massively group-sourcing translation where automated OCR has failed.

Related questions

How does Google reCAPTCHA v2 work behind the scenes?

This post refers to Google ReCaptcha v2 (not the latest version) Recently Google introduced a simplified "captcha" verification system (video) that enables users to pass the "captcha" just by clicking on it. But how can it differentiate a bot from …

Read More
How do I show multiple recaptchas on a single page?

I have 2 forms on a single page. One of the forms has a recaptcha displaying all the time. The other should display a recaptcha only after a certain event such as maxing out login attempts. So there are times when …

Read More
ReCaptcha API v2 Styling

I have not had much success finding how to style Google's new recaptcha (v2). The eventual goal is to make it responsive, but I am having difficulty applying styling for even simple things like width. Their API documentation does not …

Read More