How to generate random password with PHP?

Question

Or is there a software to auto generate random passwords?

Answer 1

Just build a string of random a-z, A-Z, 0-9 (or whatever you want) up to the desired length. Here's an example in PHP:

function generatePassword($length = 8) {
    $chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
    $count = mb_strlen($chars);

    for ($i = 0, $result = ''; $i < $length; $i++) {
        $index = rand(0, $count - 1);
        $result .= mb_substr($chars, $index, 1);
    }

    return $result;
}

To optimize, you can define $chars as a static variable or constant in the method (or parent class) if you'll be calling this function many times during a single execution.

Answer 2

here is a function that generates a password with a minimum length, a minimum number of digits and a minimal number of letters.

function generatePassword() {
$min_length=8;  //Minimum length of the password
$min_numbers=2; //Minimum of numbers AND special characters
$min_letters=2; //Minimum of letters

$password = '';
$numbers=0;
$letters=0;
$length=0;

while ( $length <= $min_length OR $numbers <= $min_numbers OR $letters <= $min_letters) {
    $length+=1;
    $type=rand(1, 3);
    if ($type==1) {
        $password .= chr(rand(33, 64)); //Numbers and special characters
        $numbers+=1;
    }elseif ($type==2) {
        $password .= chr(rand(65, 90)); //A->Z
        $letters+=1;
    }else {
        $password .= chr(rand(97, 122)); //a->z
        $letters+=1;
    }

}
return $password;   
}

Answer 3

You could just use PEAR's Text_Password package - it supports quite a few algorithms for generating them; and frees up your time to go onto something else.

Answer 4

function generate_password($length = 6) {
    $password = '';
    $chars = array_merge(range('a', 'z'), range('A', 'Z'), range(0, 9));
    for ($i = 0; $i < $length; $i ++) {
        $password .= $chars[array_rand($chars)];
    }
    return $password;
}

Answer 5

This function will include half digits and half numbers:

     function generateMixedPassword($length = 8) {
        $base = 'abcdefghijklmnopqrstuvwxyz';
        $baseD = '0123456789';

        $r = array();

        for ($i = 0; $i < $length; $i += 2) {
            $r[] = substr($base, rand(0, strlen($base) - 1), 1);
        }
        for ($i = 0; $i < $length; $i += 2) {
            $r[] = substr($baseD, rand(0, strlen($baseD) - 1), 1);
        }
        shuffle($r);

        return implode('', $r);
    }

Using the same login, it can be extended to also include special characters

Answer 6

Pwgen-php produces save, pronounceable (easier to remember) passwords: http://code.google.com/p/pwgen-php/

Might that be acceptable?