get_password.php

<?php

function get_password()
{
    $one = array(
        'A',
        'B',
        'C',
        'D',
        'E',
        'F',
        'G',
        'H',
        'I',
        'J',
        'K',
        'L',
        'M',
        'N',
        'O',
        'P',
        'Q',
        'R',
        'S',
        'T',
        'U',
        'V',
        'W',
        'X',
        'Y',
        'Z',
    );
    $two = array(
        '0',
        '1',
        '2',
        '3',
        '4',
        '5',
        '6',
        '7',
        '8',
        '9',
    );
    $three = array(
        '!',
        '#',
        '$',
        '%',
        '&',
        '(',
        ')',
        '*',
        '+',
        ',',
        '-',
        '.',
        '/',
        ':',
        ';',
        '<',
        '=',
        '>',
        '?',
        '@',
        '{',
        '|',
        '}',
        '~',
    );

    $password = array();
    foreach (array_rand($one, 4) as $key) {
        $password[] = $one[$key];
    }
    foreach (array_rand($one, 4) as $key) {
        $password[] = strtolower($one[$key]);
    }
    foreach (array_rand($two, 4) as $key) {
        $password[] = $two[$key];
    }
    foreach (array_rand($three, 4) as $key) {
        $password[] = $three[$key];
    }
    shuffle($password);

    return implode('', $password);
}