"continuous variables" . "unconditionally secure key distribution" . "quantum communication" . "Quantum key distribution" . "Quantum_key_distribution#Photon_number_splitting_attack" . "quantum key distribution" . "Quantum encryption" . "Differential phase-shift quantum key distribution" . "quantum key distribution system" . . "quantum key distribution network" . "Quantum Key Distribution" . . "quantum key distribution (QKD) system" . "Quantum cryptography" . "quantum key distribution (QKD)" . "entanglement-based quantum key distribution" . . . . "cipherkey exchange protocol" . "Quantum_key_distribution#E91_protocol:_Artur_Ekert_.281991.29" . . "photon-number-splitting attack" . . "E91" . . . . "information reconciliation and privacy amplification" . "E91 protocol" . "Quantum Communication" . . "QKD" . . "privacy amplification and information reconciliation" . "Quantum_key_distribution#S09_protocol:_Eduin_H._Serna_.282009.29" . "Quantum key distribution" .