Version 1 (modified by Sam Hocevar, 13 years ago) (diff)


PWNtcha - captcha decoder

PWNtcha stands for "Pretend We’re Not a Turing Computer but a Human Antagonist", as well as PWN capTCHAs. This project’s goal is to demonstrate the inefficiency of many captcha implementations.

For an overview on why visual captchas are a bad idea, see Matt May’s excellent presentation, Escape from CAPTCHA, as well as the W3C’s Inaccessibility of Visually-Oriented Anti-Robot Tests working draft.


I created PWNtcha in 2004 as a personal research project, but only published my results, not the program itself. Given the number of captcha-breaking software available for sale now, I changed my mind and decided to publish the PWNtcha source code. It can be downloaded from Subversion:

 svn co svn:// pwntcha

Note that PWNtcha is now lagging 3 years behind captcha technology and is therefore no longer a very interesting piece of software.