QUANTUM-KEY-DISTRIBUTION-QKD

Quantum cryptography key distribution.

Definition

QKD protocols: BB84 (Bennett-Brassard 1984, photon polarisation), B92 (Bennett 1992, non-orthogonal states), E91 (Ekert 1991, Bell pair entanglement), MDI-QKD (Measurement Device Independent), Twin-Field QKD (longer distance ~600km). Commercial implementations: ID Quantique Cerberis (>200km), Toshiba Quantum Key Distribution, QuantumCTek China (Beijing-Shanghai backbone 2000km). Limitations: limited fiber distance ~150-600km, requires dedicated hardware, slow throughput kbps-Mbps. Coexistence with PQC for hybrid schemes.

Origin

BB84 protocol published by Charles Bennett (IBM) and Gilles Brassard (Univ Montreal) 1984 ; first implementations 1989 ; ID Quantique commercialisation 2001 ; QuantumCTek China large deployment 2017+.

Example in context

China Telecom deploys a Beijing-Shanghai 2000km backbone using QKD with trusted node relays ; information-theoretic secure governmental and financial transmission.

Related terms

• ETSI QKD — European standardisation.