This addon is a plugin. You need to extract it to your /plugins folder to install it.
An alternative to reCaptcha & Captcha.
* phpCaptcha does not require any API keys * Supports limited audio captcha capabilities, Flite is not required however could be used. * Support changing font type * Background image can be set * Support using a word list * Support Captcha refresh without loosing form data * Highly customizable (manual config)
phpCaptcha share the same code as Dibonoff's Captcha 0.2.2, so swapping over should not pose any major problems.
phpCaptcha is adapted from an open source php CAPTCHA script securimage. Examples of various captcha images can be found here.