Preg_match for all special characters, password checking

Question

Ok so I am writing a password checker for our password policy which requires 3 of the 4 major classifications. Where I'm having problems with is the special character match.

Here's what I have thus far:

private function PasswordRequirements($ComplexityCount) {
    $Count = 0;
    if(preg_match("/\d/", $this->PostedData['password']) > 0) {
        $Count++;
    }
    if(preg_match("/[A-Z]/", $this->PostedData['password']) > 0) {
        $Count++;
    }
    if(preg_match("/[a-z]/", $this->PostedData['password']) > 0) {
        $Count++;
    }
    // This is where I need help
    if(preg_match("/[~`!@#$%^&*()_-+=\[\]{}\|\\:;\"\'<,>.]/", $this->PostedData['password']) > 0) {
        $Count++;
    }

    if($Count >= $ComplexityCount) {
        return true;
    } else {
        return false;
    }
}

So basically what I'm doing is checking the string for each case, numbers, uppercase, lowercase, and special characters. We don't have any restrictions on any special character and I also need unicode characters. Does the \W work in this case or would that also include numbers again? I can't find great documentation on \W so I'm unclear on this part.

Does anyone know of a easy regexp that would cover all special characters and unicode characters that does not include numbers and letters?

Anyone is free to use this as I think more than a few people have been looking for this.

Answer 1

This pattern would allow all characters that's not a digit or a-Z.

[^\da-zA-Z]

Regarding the \W it's a negated \w, which is the same as [A-Za-z0-9_]. Thus will \W be all characters that's not an english letter, digit or an underscore.

As I mentioned as a comment this is a great resource for learning regex. And here's a good site to test the regex.