Math CAPTCHA

Late last year, there were reports that hackers could successful pass CAPTCHA image test by using sophisticated character reading /recognition techniques. With this trend, software developers try to make CAPTCHA test more difficult to break by the introduction of MATH CAPTCHA.

The imges below are from some websites to protect against input by automatic scripts:

The web site will ask what is the result of the math problem shown in the image above?

It seems MATH CAPTCHA tends to offer higher level of protection as it requires human mindset to solve a math equation. But sooner or later, hackers will make it useless again.