• Authen::Captcha (Authen-Captcha)

Установка FreeBSD.

 # cd /usr/ports/security/p5-Authen-Captcha/ && make  && make install clean
 # cd /usr/ports/devel/p5-String-Random/ && make  && make install clean

Установка Ubuntu, Debian

# apt-get install  libauthen-captcha-perl

Установка с CPAN

# perl -MCPAN -e shell 
install Authen::Captcha