Re: Communication sub C
"I think it's value to crypto comes from the fact that it cant be fudged with along the way without messing up the entanglement."
That's my recollection, too, but there is nothing in the diagram that makes that point, which is a pity. As it stands in the diagram, the whole thing is open to a MitM attack. I assume there is an answer to that, but it doesn't appear to be in the article so I'm left thinking " Umm ... quantum ... magic .. awesome stuff ... too complicated for my little brain".
One shouldn't *have* to go googling in order to understand why an article is worth reading.