[BurningFrog]

I don't know the technology, but I assume that system could be built.

The bad part about that is that if I can validate my vote after the fact, someone else can also demand to see what I voted for, and that opens the door for vote buying, intimidation etc.

[EGreg]

No, not at all. You can vote anonymously and verify your vote but no one else can map that back to your identity.

As for rubber hose crypanalysis, that is possible now.

Buying votes is already done.

[BurningFrog]

You can buy the promise of a vote now, but it can't be verified on the individual level. On the precinct level you can, and that happens.