Whitelisting: You Set The Rules For Security
We all know what blacklisting is when it comes to strings: removing specified "bad" characters. While this helps to secure user input, it isn't as secure as whitelisting. Whitelisting is the process of saying "Let me tell you what you can give me" whereas blacklisting says "If I find this, I'll remove it."
A customer recently asked that I create a whitelisting function that allowed letters, digits, whitespace characters, periods, commas, and dashes. Any other characters were to be replaced with spaces.
The PHP
function make_valid($input)
{
return preg_replace('/[^A-Za-z0-9.,\(\)\s-]/',' ',$input);
}
The above function uses preg_match() and a small regular expression to remove the rubbish characters.
![Detect DOM Node Insertions with JavaScript and CSS Animations]()
I work with an awesome cast of developers at Mozilla, and one of them in Daniel Buchner. Daniel's shared with me an awesome strategy for detecting when nodes have been injected into a parent node without using the deprecated DOM Events API.
![Create a CSS Cube]()
CSS cubes really showcase what CSS has become over the years, evolving from simple color and dimension directives to a language capable of creating deep, creative visuals. Add animation and you've got something really neat. Unfortunately each CSS cube tutorial I've read is a bit...
![MooTools Documentation Search Favelet]()
I'm going to share something with you that will blow your mind: I don't have the MooTools documentation memorized. I just don't. I visit the MooTools docs frequently to figure out the order of parameters of More classes and how best to use...
![Submit Button Enabling]()
"Enabling" you ask? Yes. We all know how to disable the submit upon form submission and the reasons for doing so, but what about re-enabling the submit button after an allotted amount of time. After all, what if the user presses the "stop"...
Your way for whitelisting is quite nice. It’s like in Flash where you can specify exactly what characters are allowed by the user.
This method may work well as a common security filter that replaces get_magic_quotes_gpc(), strip_tags() and htmlentities().
Good work as usual!