Hoi-Kwong Lo
Published 2001-02-27, updated 2001-07-12Version 5
We prove the unconditional security of the standard six-state scheme for quantum key distribution (QKD). We demonstrate its unconditional security up to a bit error rate of 12.7 percents, by allowing only one-way classical communications in the error correction/privacy amplification procedure between Alice and Bob. This shows a clear advantage of the six-state scheme over another standard scheme---BB84, which has been proven to be secure up to only about 11 percents, if only one-way classical communications are allowed. Our proof technique is a generalization of that of Shor-Preskill's proof of security of BB84. We show that a advantage of the six-state scheme lies in the Alice and Bob's ability to establish rigorously from their test sample the non-trivial mutual information between the bit-flip and phase error patterns. A modified version of the degenerate quantum codes studied by DiVincenzo, Shor and Smolin is employed in our proof.
Comments: Major changes with the inclusion of important new results: we prove the unconditional security of the six-state QKD scheme up to a bit error rate of 12.7 percents using only one-way classical communications, thus demonstrating the advantage of six-state scheme over BB84. Our result makes use of i) the mutual information between the bit-flip and phase error patterns and ii) a modified version of the degenerate quantum codes studied by DiVincenzo, Shor and Smolin. Accepted for publication in the journal, QIC
Efficient Quantum Key Distribution Scheme And Proof of Its Unconditional Security
Unconditional security in quantum bit commitment
A simple proof of the unconditional security of quantum key distribution
