The CAPTCHA Project. Gimpy.

Gimpy

Gimpy is our most reliable system. It was originally built for (and in collaboration with) Yahoo! to keep bots out of their chat rooms, to prevent scripts from obtaining an excessive number of their e-mail addresses, and to prevent computer programs from publishing classified ads.

Gimpy is based on the human ability to read extremely distorted and corrupted text, and the inability of current computer programs to do the same. Gimpy works by choosing a certain number of words from a dictionary, and then displaying them corrupted and distorted in an image; after that Gimpy asks the user to type the words displayed in that image. While human users have no problem typing the words displayed, current bots are simply unable to do the same.

There are currently several versions of Gimpy. Some of them can be accessed directly through the following links:

Gimpy

Details

All the words used in gimpy are taken from an 850 word dictionary based on Ogden's Basic English. This dictionary can be downloaded below.