Ps3 – How to enumerate the installed DLCs on PS3

Some PlayStation 3 games have locked game-saves which means their game-saves are tied to the system itself. The result is that if you backup these files in a USB or an external HDD, you won't be able to use them in another system. (This is most likely done through encryption).

Here's a list of games with locked game-saves. As the list states, games without asterisks have files which are locked to the system.

However, there's a way to bring these locked game-save to another system. The PlayStation Plus service lets you upload these files to Sony's servers to be able to retrieve them in other systems. This service is not free.

You've over complicated this.

For PS3, basically once a DLC was installed on a system, any user on that system can play that DLC and earn trophies for it, whether signed in to PSN or not, I've never seen DLC which is only usable by the buying user except for items like Home items, Avatars and DLC for one specific game I know of.

So your "process" is fairly simple:

1. Log into the appropriate store for your game's region (you'll need another PS3 profile with a PSN account in that region)
2. Buy DLC from that store (funds could be from a local credit card or prepaid PSN card) and install it.
3. Log back into your main profile and account and play the DLC.

PSVita is different. A PSVita system and memory card is locked to a single user, so even if you switched the Vita's user (system restore), you'd still be only able to download the DLC to a memory card assigned to the "foreign user", meaning it won't be accessible to your "main user" (which will need its own memory card), this means that in order to buy DLC for a PSVita game, you must own a copy of the game from the same region as your main PSN user. There's no current way to avoid this (at least one that I know of), and it basically means any PSVita game that has "required DLC" like online passes, UPlay pass, etc, will only be "fully playable" if you buy games from your own region.