NSA dosn't need to break it. They just need to threaten Toshiba enough to build a backdoor for them.
If you have to brute force the key, then you'll be sitting around well past the end of the universe and not even be anywhere close to the keyspace.
But your overall gist is correct.
Guys, lets get this straight: symmetric key encryption (private key) is unbreakable.
This doesn't mean that your data is safe because you Truecrypted it- anything from "camera watches you type password" to "tiny device reads your password" to "man hits you with bat until you tell password" are ways to attack this. But the algorithms are secure.
In any event, the advance is legit. But it doesn't do what the headline says any more than existing technology does. What it DOES offer is a solid engineering advance in this field.
I need to buy some toshiba stock.
I remember almost a decade ago first coming across the idea and thought it'd be pretty cool, but, yeah, just like entanglements, while cool in concept and enabling sci-fi writers to go nuts, in actual practically physics says you can't use this for anything super cool or practical. That is, so long as the quantum model holds, the moment its broken (and most people are pretty certain that while it works, it's a model of convenience and it only happens to work very well, like Newton's methods all the way up to the atomic scale) there may be a means to apply these things in fun methods.
What are you willing to sacrifice?
So? If this became common usage they would just have to resort to old school cracking, as in always attack the weakest link. If the math is no longer the weakest then that means that it's YOU. So instead you'll be locked in a basement with some scarey looking people that will do unspeakable things to you until you tell them your password or what they want to know. Take your pick ...
Concidering people cant even manage to install and use PGP properly I wouldn't really put this high on the list over things to worry about if I was the NSA.