Security of the Bennett 1992 quantum-key distribution protocol against individual attack over a realistic channel
- CREST Research Team for Interacting Carrier Electronics, School of Advanced Sciences, Graduate University for Advanced Studies (SOKENDAI), Hayama, Kanagawa 240-0193 (Japan)
The security of two-state quantum-key distribution against individual attack is estimated when the channel has losses and noises. We assume that Alice and Bob use two nonorthogonal single-photon polarization states. To make our analysis simple, we propose a modified B92 protocol in which Alice and Bob make use of inconclusive results, and Bob performs a kind of symmetrization of received states. Using this protocol, Alice and Bob can estimate Eve's information gain as a function of a few parameters that reflect the imperfections of devices, or Eve's disturbance. In some parameter regions, Eve's maximum information gain shows counterintuitive behavior, namely, it decreases as the amount of disturbances increases. For a small noise rate, Eve can extract perfect information in the case where the angle between Alice's two states is small or large, while she cannot extract perfect information for intermediate angles. We also estimate the secret key gain, which is the net growth of the secret key per pulse. We show the region where the modified B92 protocol over a realistic channel is secure against individual attack.
- OSTI ID:
- 20633825
- Journal Information:
- Physical Review. A, Vol. 67, Issue 3; Other Information: DOI: 10.1103/PhysRevA.67.032310; (c) 2003 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
Similar Records
Quantum steganography with noisy quantum channels
Secrecy extraction from no-signaling correlations