Accessing the mac app store user id?

Salutations all. I know this isn’t technically an iOS question and thus might not belong in this forum but it was the most appropriate one I could find. I’m interested in distributing a game via the mac app store, and I want buyers to be able to install the game on as many macs as the app store allows (will be infinite if I can pick the upper limit).

Right now I’m using regular serials, this has to go when the game is on the app store for obvious reasons. The problem is that my way of differentiating between users is said serial. I don’t require a sign-up, they can change their nickname every time they play if they so desire. Thus the app store is presenting me with a problem.

I could skip the auth phase entirely, of course, but then it’d be impossible to include accurate leaderboards of any kind. It’d also be impossible to keep their progress synced between the various computers they use to play the game with. Could also require a sign-up, but I’d like to prevent my players from having to go through that whole ordeal if at all possible.

Is there any kind of unique identifier or token associated with a user’s mac app store account that can be accessed to identify them and thus fetch their particular data? It has to be consistent between all the macs they use to play the game with (thus no hardware ids). Pardon if this readily available information, I’ve spent the last four hours trying to find anything like it. But my google-fu has failed me in the past.

I also want to download some games from the App store however some interesting games requires payment or they are the trial version.

I suppose I should be thankful that there was a reply but… uh, yeah, spam maintenance required.

Was hoping to find this for both Android and IOS. Having the same problems locating via google. Seems like if you want to share info across devices for the same user (they have an Iphone/IPad), using the store ID would be the way to go. Should be easier to find this info!