androvsky said:
How is any of this supposed to work with the Vita?
A disc is proof that you have the game, so it acts as the "signature." Yeah, you can easily copy a disc, so it's susceptible to piracy, but it's pretty secure.
A signature can be anything. It doesn't have to be a disc. If you can prove you own the game, that's good enough to act as a signature. Here's a scenario which Sony has abandoned in favour of the more profitable route.
1. PSP validates the disc against Sony's servers.
^ This is clearly feasible, since the press release says you can only register each disc once. You're essentially doing the same thing here.
2. If it's a non-used disc, your PSN account gets a flag giving you permission to play that game from a Vita's memory stick.
3. The game is packaged and transfered.
4. Each time you load the game, it checks your account against Sony's servers to ensure you have permission to play this game. A token could even be stored, giving you permission to play it for x days before needing to check the server again.
This is exactly the same as installing to your HDD from a technical standpoint the only difference is the way the signature is created/checked (and actually far more secure against piracy than HDD install, since Sony has remote control over your access to the software).
The only reason Sony did not choose this route is because it will cost them money. But sometimes you have to spend money to gain loyalty and, eventually, sell more hardware/software.