README

This is a PHP class for generating images with simple mathematical questions (Math CAPTCHAs) to protect the forms of your website from spambots.

How to Install:

You can install the class very easily by using composer. You just have to run:

composer require magkopian/php-math-captcha:1.0.*

Or add it as a dependency in you composer.json file:

{
	"require": {
		"magkopian/php-math-captcha": "1.0.*"
	}
}

And then run:

composer update

Also, don't forget to include composer autoload.php file to your code.

How to Use:

To generate a captcha you simply:

session_start();

$mathCaptcha = new MathCaptcha\MathCaptcha();

$mathCaptcha->generate();
$mathCaptcha->output();

The MathCaptcha class makes use of session variables so you have to call the session_start() function before instantiating a MathCaptcha object.

You can optionally supply an identifier for the captcha, to the constructor of the MathCaptcha class, if you want to use multiple captchas in your website.

To verify the user's answer you simply:

session_start();

$mathCaptcha = new MathCaptcha\MathCaptcha();

if ( $mathCaptcha->check($captcha_answer) === true ) {
	// Correct answer
}
else {
	// Incorrect answer
}

If you use more than one captchas in your website you need also to supply the identifier of the captcha, to the constructor of the MathCaptcha class.

Check out the test_form.php and math_captcha.php files for a working example.

Requirements:

PHP 5, GD 2.0.1 or later (2.0.28 or later is recommended)