Presentation

GcaptchaZ is a command line captcha generator. This is a C transcription of Loz's PHP captcha generator with some modifications.

Main modifications

Group letters
Add another layer for letter rendering (more confusing)
Change start, not appropriate for big fonts
Change min/max font size

Recommandations

You need libgd2-xpm-dev package to compile the project or libgd2-xpm to use binaries.

It's recommanded to use the "scrawl.ttf" font (included).

Usage

./gcpatchaz [-w WIDTH] [-h HEIGHT] [-o OUT.PNG] [-f FONT] [-s STRING]

generate_captcha.sh

The package also includes "generate_captcha.sh", this is a simple script to generate a captcha and rename it with the captcha's value encrypted (AES 128) with a md5 of the AES key.

This allow to retrieve captcha's value only with its name if you have the right AES key and also to use a passphrase. It's usefull to generate static captchas.

The script also contains a visual verification to avoid generating hard to resolve captchas.

Usage

generate_captcha.sh OUT_DIR PASSPHRASE

Licence

Copyleft, Licence Art Libre (http://artlibre.org/licence/lal)