# Introduction to Zend\\Captcha

[CAPTCHA](http://en.wikipedia.org/wiki/Captcha) stands for "Completely Automated Public Turing test
to tell Computers and Humans Apart"; it is used as a challenge-response to ensure that the
individual submitting information is a human and not an automated process. Typically, a captcha is
used with form submissions where authenticated users are not necessary, but you want to prevent spam
submissions.

## Overview

Captchas can take a variety of forms, including asking logic questions, presenting skewed fonts, and
presenting multiple images and asking how they relate. The `Zend\Captcha` component aims to provide
a variety of back ends that may be utilized either standalone or in conjunction with the
\[Zend\\Form component\](zend.form.intro).