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A Simple Proof of the Unconditional Security of Quantum Key Distribution
Lo, HoiKwong
HPL199963
Keyword(s): quantum cryptography; quantum information; quantum computation; unconditional security
Abstract: Quantum key distribution is the most wellknown application of quantum cryptography. Previous 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 invariance of 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 nontrivial 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 faulttolerant 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.
13 Pages
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