cs cart unsubscribe key generation

gistfile1.php

 $_data = array(
                   'subscriber_id' => $subscriber_id,
                   'list_id' => $list_id,
                   'activation_key' => md5(uniqid(rand())),
                   'unsubscribe_key' => md5(uniqid(rand())),
                   'email' => $subscriber['email'],
                   'timestamp' => TIME,
                   'lang_code' => $lang_code,
                   'confirmed' => ($_confirmed == NULL) ? (!empty($lists[$list_id]['register_autoresponder']) ? 0 : 1) : ($_confirmed ? 1 : 0),
                   'format' => intval($format)
               );