Object CAPTCHA: Perform CAPTCHA validation using object images

README
------

We must connect to a db for this to work
========================================
1. create a database
2. import objectcaptcha.sql in it
3. set your credentials in db.php


ObjectCaptcha works in two steps
================================
* First (in index.php) an image is grabbed, the answer saved to the db,
then the registration form displayed.
* Second (in register.php) the answer from the db is compared to the input from
the form.


Some notes on ObjectCaptcha
===========================
* A random jpg image will be displayed each time (and its answer saved to the db).
* The answer to an image is the image's filename.
* Multiple answers can be given for an image.
They have to be separated with underscores in the image's filename.
For example, for: boot_shoe.jpg the answer can be either 'boot' or 'shoe'
* ObjectCaptcha needs a db to temporarily store answers, because it would be
unsafe to store them in cookies.
* Images are encoded in base64 format and displayed like that, so their original
filename cannot be retrieved.
* Random garbage is added to the end of an image (JPEG allows this)
to protect against hash attacks on the image.
* I originally created ObjectCaptcha as a mod for SMF forum.
This is a more generic relase that can be used with other systems.


Files
=====
These are example files, not needed on a production site:

db.php
index.php
register.php
readme.txt
screenshot.png

objectcaptcha.sql is needed only for installation.

Any .jpg file placed in the directory will be used by the Captcha.