password-generator.php

<?php
// Generates a strong password of N length containing at least one lower case letter,
// one uppercase letter, one digit, and one special character. The remaining characters
// in the password are chosen at random from those four sets.
//
// The available characters in each set are user friendly - there are no ambiguous
// characters such as i, l, 1, o, 0, etc. This, coupled with the $add_dashes option,
// makes it much easier for users to manually type or speak their passwords.
//
// Note: the $add_dashes option will increase the length of the password by
// floor(sqrt(N)) characters.

/**
 * Generate password
 * source: https://gist.github.com/tylerhall/521810
 */
function generateStrongPassword($length = 9, $add_dashes = false, $available_sets = 'luds')
{
    $sets = array();
    if (strpos($available_sets, 'l') !== false) {
        $sets[] = 'abcdefghjkmnpqrstuvwxyz';
    }
    if (strpos($available_sets, 'u') !== false) {
        $sets[] = 'ABCDEFGHJKMNPQRSTUVWXYZ';
    }
    if (strpos($available_sets, 'd') !== false) {
        $sets[] = '23456789';
    }
    if (strpos($available_sets, 's') !== false) {
        $sets[] = '!@#$%&*?';
    }
    $all = '';
    $password = '';
    foreach ($sets as $set) {
        $password .= $set[array_rand(str_split($set))];
        $all .= $set;
    }
    $all = str_split($all);
    for ($i = 0; $i < $length - count($sets); $i++) {
        $password .= $all[array_rand($all)];
    }
    $password = str_shuffle($password);
    if (!$add_dashes) {
        return $password;
    }
    $dash_len = floor(sqrt($length));
    $dash_str = '';
    while (strlen($password) > $dash_len) {
        $dash_str .= substr($password, 0, $dash_len) . '-';
        $password = substr($password, $dash_len);
    }
    $dash_str .= $password;
    return $dash_str;
}