N ov 2 00 7 Key rate available from incompatible mesurements in the BB 84 protocol and the uncertainty principle

Key Rate Available from Mismatched Mesurements in the BB 84 Protocol and the Uncertainty Principle ∗

SUMMARY We consider the mismatched measurements in the BB84 quantum key distribution protocol, in which measuring bases are different from transmitting bases. We give a lower bound on the amount of a secret key that can be extracted from the mismatched measurements. Our lower bound shows that we can extract a secret key from the mismatched measurements with certain quantum channels, such as the...

ar X iv : 0 71 2 . 14 94 v 1 [ qu an t - ph ] 1 0 D ec 2 00 7 Improved one - way rates for BB 84 and 6 - state protocols

We study the advantages to be gained in quantum key distribution (QKD) protocols by combining the techniques of local randomization, or noisy preprocessing, and structured (nonrandom) block codes. Extending the results of [Smith, Renes, and Smolin, quant-ph/0607018] pertaining to BB84, we improve the best-known lower bound on the error rate for the 6-state protocol from 14.11% for local randomi...

ar X iv : h ep - t h / 02 11 04 8 v 1 7 N ov 2 00 2 Inflation , Quantum Cosmology and the Anthropic Principle 1

ar X iv : q ua nt - p h / 04 12 07 0 v 4 2 4 Ju n 20 05 Noise Tolerance of the BB 84 Protocol with Random Privacy Amplification ∗

This paper shows that the BB84 protocol with random privacy amplification is secure with a higher key rate than Mayers’ estimate with the same error rate. Consequently, the tolerable error rate of this protocol is increased from 7.5 % to 11 %. We also extend this method to the case of estimating error rates separately in each basis, which enables us to securely share a longer key.

A quantitative algebraic analysis of BB’84 with maximal entropy

The paper provides a quantitative algebraic analysis of a BB’84-type quantum key distribution protocol. The analysis is done in an algebraic setting, where classical and quantum variables form a module for the quantale formed from the communication and quantum actions. The module-quantale pair is endowed with sup-maps that encode uncertainties of agents involved in the protocol, about the varia...