QKD (Quantum Key Distribution)

QKD is a cryptographic technique that uses quantum-mechanical phenomena — most commonly single photons — to securely distribute an encryption key between two parties, with a guarantee that any eavesdropping attempt is detected.

How does QKD work?

Information is encoded in the quantum states of single photons (e.g. polarization), and a fundamental principle of quantum mechanics says that any measurement of such a state by an eavesdropper inevitably disturbs it. The communicating parties can detect such disturbance through statistical analysis of a portion of the transmitted data, discarding the key if eavesdropping is detected.

Applications

QKD is used in telecommunications networks requiring the highest level of security — government, financial, and military communications — as a complement or alternative to classical cryptography, resistant to future quantum-computer attacks.

Related terms

Coherent detection

PIC (Photonic Integrated Circuit)

DWDM