Quantum entanglement

Physics

Pathology

Cryptography

Key (lock)

Postselection

Computer network

Quantum cryptography

Artificial intelligence

Lossy compression

Quantum information

Alternative medicine

Protocol (science)

Computer science

Quantum mechanics

Theoretical computer science

Quantum key distribution

Computer security

Medicine

Quantum

Physical Review Applied

In quantum cryptography, the twin-field (TF) quantum key distribution (QKD) protocol could extend theoretical key rates through a lossy channel, but most of its security proofs require phase postselection, which complicates practical systems and severely limits secure key rates. This study presents a truncated TF-QKD protocol without any postselection, gives a general security proof, and shows that this scheme may beat other protocols in terms of key rate, even when only finite decoy states are employed. By showing that a medium-range QKD system can reach much higher key rates, this protocol will make QKD systems more applicable in tomorrow's cybersecurity.

Twin-Field Quantum Key Distribution without Phase Postselection