Is it possible to tie a subscription to a iTunes account with in-app purhcase?
<p>We're trying to implement a subscription service with in-app purchase in our app. The problem is our service does not require a user account for the past year of service. Users simply use this service with advertisements shown. We want to give them a subscription where they can buy for say, 3 months to have the advertisement removed.</p>

<p>How can this be done? We'll have to make it 
a consumable because it is a subscription. But we wouldn't know when the subscription end. </p>

<ul>
<li>We can't save the state locally
because the user might reinstall the app</li>
<li>We can't save the state on the server and tie it to their device because sometimes the user changes device</li>
<li>We don't have a user account to tie the subscription to and we don't want to introduce a user account system which spoils the experience.</li>
</ul>

<p>Is there some way of associating the purchase with their iTunes account? So that it is carried with them when they reinstall or changes device?</p>
