Configurable Captcha generator for Code Igniter

What is a captcha ?

What is Code Igniter ?

Requirements ?

Contents of the zip file ?

How to install ?

Configure how and what ?

How to call ?

How to check ?

Some Samples

Download

Thanks

What is a captcha ?

A captcha is an image containing a code made of random alphanumeric characters.
They are integrated into websites, generaly in forms, to verify if the user is an human or not (robot).
So that the goal is also to scramble OCR detection, it contains generaly some jamming informations
(blur background, blur characters, jamming lines,...).

What is Code Igniter ?

CI is a PHP based MVC (Model View Controller) framework.
You will find more about Code Igniter here.

Requirements ?

1. Knomledge of PHP and Code Igniter ...
2. Code Igniter framework
3. GD installed on your webserver
4. Session library enabled on your CI controller or autoloaded

Contents of the zip file ?

How to install ?

Configure how and what ?

It is very easy and all the configurable parameters, with their explanations, are in the file "sig_config.php".

What can you configure ?

• the use of an existing (jpeg or png) background image
• otherwise the background color to use
• and the size of the image to generate
• which group of characters to use
• which font face to use
• which size(s) to use (fixed or variable)
• which angle(s) to give to each character (fixed or random in a range)
• the number of characters to use to build the code
• the distance between the characters
• padding top and bottom for the characters in the image
• where the text horizontaly begin in the image
• the color of the characters
• to use or not shadowed characters
• the distance of the shadow
• the color of the shadow
• to use parallel horizontal symetrical jamming lines
• to use parallel horizontal randomly placed jamming lines
• to use horizontal randomly angled and placed jamming lines
• the number of those horizontal lines to use
• to use parallel vertical symetrical jamming lines
• to use parallel vertical randomly placed jamming lines
• to use vertical randomly angled and placed jamming lines
• the number of those vertical lines to use
• to use elliptical jamming
• the number of ellipse
• to use rectangular jamming
• the number of rectangles
• to use polygonal jamming lines
• the number of polygonal jamming lines
• the color of the jamming lines and forms

How to call ?

When you want to generate a security image you just have to point it as http://domain/sig

In the form it would looks like this :

<form headers ... >
...
Validation Code:
<img src="<?php echo base_url().'sig'; ?>" alt="CAPTCHA">
<input type="text" name="code" size="10">
...
</form>

How to check ?

To check the captcha agains the input form code, just add something like this :

if ($this->input->post('code') != $this->session->userdata('sig_key')) { echo 'error'; } else { echo 'success'; }

or like this :

if ($this->input->post('code') != $this->obj->db_session->userdata('sig_key')) { echo 'error'; } else { echo 'success'; }

on the controller/file that does your submit.

Some Samples

Download

Feel free to download it, use it and modify it like you want.

SecurityImageGenerator.zip

Thanks

Special thanks to Stupid Shrimp (Baka Ebi) who developped his captcha generator and on which this one is based.