I have made a macro  based addin myself and have done what you require. Once
you have created your addin and pasword protected  it, you take the addin you
created to another computer,
In excel  go to tools -> addins -> Browse .... Open the directory where you
have placed your addin and say OK.
If your macro is properly built to setup the menu  created by you then
everything will be fine.

The password  protected addin will not be available for viewing by the users.