MathGuard PHP form anti-spam protection
Creating this website made with PHP, I attracted lots of spambots to flood my forum, my programming resources, freelance database and other forms, but you probably know this situation very well. So I decided to create a simple anti-spam PHP Class which could help me and probably other people to deal with the spam.
MathGuard is free PHP class that everyone can use as anti-spam protection for the website forms. It's also a suitable solution when there is no PHP GD support from the webhosting company.
UPDATE: MathGuard version 3.0
Here's an example how to use MathGuard to protect your forms (Adobe Flash player required)
New version features a better way of rendering the expression that user has to evaluate. The numbers consist of 3x5 random character matrix.
Download UPDATED version MathGuard
Go to the download section on this website and find there mathguard-v3.0.zip
Installation process is the same as in the version 2.0, so please install it the way it is described below.
The older version - MathGuard 2.0
You can still install the older version:
You have probably seen this solution before on some other websites, it's nothing new,
The principle of this PHP anti-spam class
The principle of this PHP anti-spam class is very simple - The class inserts a small piece of HTML code into your PHP form -
When user submits the form with the answer, the answer is being hashed and compared to
How to set up this PHP anti-spam class and use it on your website?
1. Download the code of MathGuard
Current version is 2.0
Go to the download section on this website and find there mathguard-v0.2.zip
2. Unzip the archive
and copy the file ClassMathGuard.php into the folder with forms and action handlers you want to use.
3. Open the code with the PHP or HTML form you want to protect
4. Add the following PHP code snippet (the one in the ellipse)
5. Protect the form handler
/* first we need to require our MathGuard class */
6. Open the form in your browser and you should see the mathguard's anti-spam security question there
7. Example - watch the flash demo above
8. Enjoy !
If you'd have any questions regarding my PHP anti-spam class, feel free to write to the comments or directly to my email