Hi blin_1,
As for the issues relating to data authorization and security, we provide simple guidelines in Section 4.1 of
this document.
In this regard, the implementation of some methods of the Metadata Adapter interface allow you to authenticate users and allow subscriptions only from user sessions regularly signed up.
In addition for your case you could implement in
getItems some logic for customized Item names or Item names used only once.
Finally, have you the possibility to use SSL connections?