Secure random password generator

/**
 * Generates and returns a random password, of a random length between min and max.
 *
 * Hard limits are minimum 10 chars and maximum 72.
 *
 * @author Christian Fagerheim (Fagerheim Software)
 * @link www.fagsoft.no
 * @license Creative Commons Attribution-ShareAlike 3.0. http://creativecommons.org/licenses/by-sa/3.0/.
 *
 * @param int[optional] $minLen = 10
 * @param int[optional] $maxLen = 14
 * @return string
 */
function generatePassword ($minLen = 10, $maxLen = 14) {
    if ($minLen < 10) {
        $minLen = 10;
    }

    // Discard everything above 72 characters for the password (bcrypt limitation).
    if ($maxLen > 72) {
        $maxLen = 72;
    }

    $numChars = mt_rand ($minLen, $maxLen);

    // Create an secure random password, and cut it down to length.
    $password = base64_encode (mcrypt_create_iv (256, MCRYPT_DEV_URANDOM));
    $password = substr ($password, 0, $numChars);

    // Define the replacements sets and values for strtr ().
    $find = "10lIO";
    $replace = "_-*!?";

    // Replace the similar-looking characters with special characters.
    $password = strtr ($find, $replace, $password);

    // Save the hashed password in the object, and return it to calling method.
    return $password;
}