Captcha Breaker

ALL software unless otherwise noted is distributed 
under the GPL-3 License (c) 2006-2007 Abram Hindle
see GPL-3.0, LICENSE and/or HACKING

You will need ocaml to compile this

For ubuntu/debian install the following packages:

libcamlimages-ocaml
libcamlimages-ocaml-dev
libocamlgsl-ocaml
libocamlgsl-ocaml-dev
ocaml-findlib
ocaml-native-compilers
m4
make

Ocaml 3.09.2 is recommended
m4 is needed
Make is needed

make phpbb digg seedpeer piratebay

Should build the captcha breakers, they need fonts though.


PHPBB comes with an example font file

The captcha breakers expect a:
segments directory
fonts directory
in their current directory

I can't distribute copyrighted captchas so I just show the font skeleton. You
can probably make your own "font" for whatever site you want. I can't limit
what you do with this software other than how you license it. Please read
GPL-3.0 to understand your rights.

./phpbb imagefile.gif

The last line will contain the guess of the captcha.

========= How do I break a captcha =======
Read this giant image final.medium.png

1. CLean up the image
2. Segment the image
3. Annotate the segments per letter
3.1 Make a font directory
4. Define a solver which uses that font (see phpbb for example)

====== What are the limitations ========

I couldn't get shape matching working very well:

http://www.eecs.berkeley.edu/Research/Projects/CS/vision/shape/mori-gimpy.pdf

I can solve linear transformations like skew and rotation but
non-linear warps are difficult. E.g. google/aim/yahoo.

This code here is more of a repository of attempts at breaking
captchas, some successful, some not.

Other interesting work to look at includes:

http://www.ceas.cc/papers-2005/160.pdf

Essentially with enough time (1-2 weeks) I could probably get even
google done. It is just a lot implementation and testing.

======= This is wrong! ======

Read this giant image final.medium.png (linked at the top)

I pose a reasonable argument. I think it limits us too much and limits
progress. It especially harms those who use alternative software to view
standard web pages and the disabled (who probably use such software).

You shouldn't rely on really poor security. Perhaps make your users smarter,
there are other methods of verifying a warm body is behind a keyboard.

====== Contact Info =======

captchas at churchturing dot org

===== I hate you =====

I hope you enjoy the yellow on blue text then.

===== Your Documentation Sucks ====

I have no incentive to make them any better ;)

===== Your code Sucks ====

Hey! >:(