Submarines employ random "keys" known as one-time pads to encrypt messages. Each key can only be used once, making it impossible for eavesdroppers to crack the code.No, QKD does not solve these problems. Conventional cryptography solves the first
One problem with this is that the key must be securely agreed before the submarine leaves base. There is a risk involved in having many keys on board, in case the sub is captured and they fall into hostile hands.
The other problem is that submarines receive messages using low-frequency radio waves that can penetrate water, but only a few characters per second can be transmitted at these frequencies. To receive high frequencies, which can boost the data rate, submarines have to surface and risk detection. ...
He suggests that a technique called quantum key distribution (QKD) could solve these problems.
problem. QKD does nothing about the second.
To establish a secure link while remaining 100 metres underwater, submarines could transmit photons of laser light to satellites, for retransmission to base. With the key exchanged, the submarine could then communicate via laser pulses with guaranteed security.If the submarines are close enough to the surface that they can communicate with laser beams, then they do not need the low-bandwidth radio waves of the 2nd problem. Regardless, trying to control the quantum state of the photons will not solve any problems.
This is crackpot stuff. No military submarine would ever try to use anything so crazy. Why aren't there any quantum physicists debunking this nonsense?