* The hash to verify the password against.
* @return
* <ul>
- * <li><code>null</code>, if the password was valid</li>
+ * <li><code>null</code>, if the password was invalid</li>
* <li><code>hash</code>, if the password is valid and the hash
* doesn't need to be updated</li>
* <li>a new hash, if the password is valid but the hash in the