A simple proof of the unconditional security of quantum key distribution

Quantum key distribution is the best known application of quantum cryptography. Previously proposed proofs of security of quantum key distribution contain various technical subtleties. Here, a conceptually simpler proof of security of quantum key distribution is presented. The new insight is the invarianceof the error rate of a teleportation channel: we show that the error rate of a teleportation channel is independent of the signals being transmitted. This is because the non-trivial error patterns are permuted under teleportation. This new insight is combined with the recently proposed quantum-to-classical reduction theorem. Our result shows that assuming that Alice and Bob have fault-tolerant quantum computers, quantum key distribution can be made unconditionally secure over arbitrarily long distances even against the most general type of eavesdropping attacks and in the presence of all types of noises. PACS numbers: 03.67.-a, 03.65.Ta

• Type: Journal
• Year: 1999
• Where: CORR
• Authors: Hoi-Kwong Lo
• Keywords: CORR 1999, Education, Error Rate, Quantum Key Distribution, Teleportation Channel