Create preg_match for password validation allowing (!@#$%)

Question

I would like to create a preg_match function to validate my passowrds, but I\'m not sure how to write it to allow the following special characters to be used: <

Answer 1

A different way

Let look different to this, I believe that users can use all of the ASCII valid characters (32 < ascii_code < 127) in the password and created a function that checks all the characters that are is in ASCII table!

function check($pass, $i = 0){
     if(strlen($pass) > $i)
         return (0rd(pass[$i]) > 32 and 0rd(pass[$i]) < 127) and check($pass, $i + 1);
}

Usage

if(!check($_POST["password"])){
    echo "password is wrong";
}

Answer 2

I think this should look like that:

if(!preg_match('/^(?=.*\d)(?=.*[A-Za-z])[0-9A-Za-z!@#$%]{8,12}$/', $password)) {
    echo 'the password does not meet the requirements!';
}

Between start -> ^
And end -> $
of the string there has to be at least one number -> (?=.*\d)
and at least one letter -> (?=.*[A-Za-z])
and it has to be a number, a letter or one of the following: !@#$% -> [0-9A-Za-z!@#$%]
and there have to be 8-12 characters -> {8,12}

As user557846 commented to your question, I would also suggest you to allow more characters, I usually (if i use a maximum) take at least 50 :)

btw, you might want to take a look at this regex tutorial

Answer 3

if (!preg_match('/^(?=.*\d)(?=.*[A-Za-z])(?=.*[!@#$%])[0-9A-Za-z!@#$%]
{6,15}$/',($_POST['password']))) {
    $message='Password must contain 6 characters of letters, numbers and 
    at least one special character.';
}

Answer 4

Look up character classes, a basic feature of regular expressions.

Answer 5

if(!preg_match('/^(?=.*\d)(?=.*[A-Za-z])[0-9A-Za-z!@#$%]{8,12}$/', $password)) {
    echo 'the password does not meet the requirements!';
    }

In the above statement.. what possible password thus exist?.

Answer 6

I have developed a complete regex for a bit more complex check

/^(?=.*\d)(?=.*[A-Za-z])(?=.*[A-Z])(?=.*[a-z])(?=.*[ !#$%&'\(\) * +,-.\/[\\] ^ _`{|}~\"])[0-9A-Za-z !#$%&'\(\) * +,-.\/[\\] ^ _`{|}~\"]{8,50}$/

Basically I check for the password to have 1 digit, 1 capital, 1 lower and 1 special character. I hope this helps someone looking for a regex.