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Introduction

This package provides the functionality to create Numeral CAPTCHAs (Completely Automated Public Turing tests to tell Computers and Humans Apart). Features include:

• Creating numerical Captchas
• Generic information about the Text_CAPTCHA_Numeral

The package creates numeral CAPTCHAs; due to the stateless nature of the HTTP protocol, the logic to secure a webpage using the package must be specifically implemented. See the usage example for detailled information.

Example

The following example implements the standard use of a CAPTCHA: Submitted form data is only evaluated when a CAPTCHA has been solved correctly.

Creating a Numeral CAPTCHA

This example is just to show you how to generate a simple mathematic operation with Text_CAPTCHA_Numeral.

<?php
require_once 'Text/CAPTCHA/Numeral.php';
$num       = new Text_CAPTCHA_Numeral;
$operation = $num->getOperation();

/**
 * This will print the mathematical operation
 * that has been generated by the package.
 */
print $operation;
?>

Securing a form with a Numeral CAPTCHA

This example will show you how to secure a form using the numeral captcha. It generates an operation and stores its result into a session variable.

<?php
require_once 'Text/CAPTCHA/Numeral.php';
$numcap = new Text_CAPTCHA_Numeral;

if (isset($_POST['captcha']) && isset($_SESSION['answer'])) {
    if ($_POST['captcha'] == $_SESSION['answer']) {
        $errors[] = 'Ok... You might be human...';
    } else {
        $errors[] = 'You are dumb or not human';
    }
}
    if (!empty($errors)) {
        foreach ($errors as $error) {
            print "<h1><font color='red'>$error</font></h1><br />";
        }
    }


    print '
        <form name="capter" action="index.php?page=liveExample" method="post">
         <table>
          <tr>
           <th>What is this result pilgrim?: '.$numcap->getOperation().'</th>
           <td><input type="text" value="" name="captcha" /></td>
          </tr>
          <tr>
           <th/>
           <td><input type="submit" value="Let me prove you that I am human!" /></td>
          </tr>
        </form>
    ';
    $_SESSION['answer'] = $numcap->getAnswer();
?>

Information about the Text_CAPTCHA_Numeral and inner workings

Text_CAPTCHA_Numeral gives you the ability to generate numerical mathematical captchas.

• getOperation() generates the operation that is going to be shown to the end user. getAnswer() Gets the answer of the generated operation's answer.