Another response already mentioned one aspect of how this can be used for secure communication, for detecting signal interception. But there’s a second aspect a

Another response already mentioned one aspect of how this can be used for secure communication, for detecting signal interception. But there’s a second aspect as well. Since the signaling is broken up into two parts (send the entangled state, send the measurement result), both parts have to be intercepted to decode the communication. The entangled state can be sent over a secure channel in advance, and the measurement sent over an insecure channel at the time of information transmission. This is analogous to sharing a one-time pad in advance, but the key distinction is that the no-cloning theorem guarantees that it’s impossible for someone to have stolen a copy of your one-time pad. They can only have stolen your one time pad, in which case you would notice.