You can only use qkd if you already have a shared key. If you already have that you can also use that to distribute your keys. Impractical and expensive becaus

You can only use qkd if you already have a shared key. If you already have that you can also use that to distribute your keys. Impractical and expensive because: * You need a glas fiber line. That means no copper, no wifi, no crypto on mobile phones. * You are limited to some tens to hundreds of kilometers. No transatlantic encrypted qkd. It doesn't work. * Complex physical tasks with high accuracy like sending and detecting single photons - not cheap.