Quantum Key Distribution (QKD)

Quantum key distribution (QKD) is the use of laser beams to transmit cryptographic keys securely using the quantum properties of photons in laser beams. The photons are coded in binary ones and zeroes which are then picked up by the receiving equipment. This makes it possible to transmit keys without them being intercepted.

Quantum key distribution exploits quantum mechanics to transmit keys between two parties securely. While a key, or a one-time pad, is theoretically unbreakable, the key challenge is getting both parties in a conversation to agree to the same key without the key being intercepted by a third party.

Quantum key distribution uses lasers to transmit the keys. The quantum properties of photons in the beams are coded into binary ones and zeroes. While a third party can intercept the beam, by being observed, the quantum properties change, making the keys useless to an attacker.

A practical application of the technique is secure communication between submarines. Commercial QKD systems are aimed at those with a need for high security, such as the defense industry.