Quantum encryption is solving a non-problem. It provides a mechanism which guarantees that a message sent over a point-to-point optical link hasn't been intercepted. However:
* It is orders of magnitude slower than normal data transmission.
* The range is limited.
That makes it suitable for key exchange between two switches connected by a fibre. However Diffie-Hellman key exchange does this perfectly well already, if you need it. Also quantum encryption can't survive going through any kind of forwarding other than an optical circuit switch, so as soon as you do anything higher level you need to decrypt and re-encrypt the data, breaking the physical guarantees.
When you look at the security threats to modern communication, physical taps are way down the list. Security is already built on the idea that the network is compromised, so end-to-end encryption is already the norm. Adding quantum encoding buys you nothing.
* It is orders of magnitude slower than normal data transmission.
* The range is limited.
That makes it suitable for key exchange between two switches connected by a fibre. However Diffie-Hellman key exchange does this perfectly well already, if you need it. Also quantum encryption can't survive going through any kind of forwarding other than an optical circuit switch, so as soon as you do anything higher level you need to decrypt and re-encrypt the data, breaking the physical guarantees.
When you look at the security threats to modern communication, physical taps are way down the list. Security is already built on the idea that the network is compromised, so end-to-end encryption is already the norm. Adding quantum encoding buys you nothing.