Quantum entanglement

Quantum computers use “qubits” which hold both zero and one at the same time. A quantum network can transmit them via quantum entanglement. You can create particles that are “entangled.” If you then observe the state of one of them, you’ll affect the state of its entangled partner, no matter how far away that other particle is.

You can use that to encrypt information. If a sender wants to send a message to a receiver, each would receive one of a pair of entangled photons. Measuring those photons’ states would give both a unique key, which is used to encrypt a message, and in turn to decrypt it. If somebody tried to tap in for the key, that would influence the photons, and both parties would be alerted.

Because the distance does not matter, it is possible to create pure (extremely fast) bandwidth of transmission of information between entangled particles. This process is described in teleportation.