| Item type |
学位論文 / Thesis or Dissertation(1) |
| 公開日 |
2010-02-22 |
| タイトル |
|
|
タイトル |
Security analysis of the Bennett 1992 quantum key-distribution protocol over a realistic channel |
| タイトル |
|
|
タイトル |
Security analysis of the Bennett 1992 quantum key-distribution protocol over a realistic channel |
|
言語 |
en |
| 言語 |
|
|
言語 |
eng |
| 資源タイプ |
|
|
資源タイプ識別子 |
http://purl.org/coar/resource_type/c_46ec |
|
資源タイプ |
thesis |
| 著者名 |
玉木, 潔
|
| フリガナ |
タマキ, キヨシ
|
| 著者 |
TAMAKI, Kiyoshi
|
| 学位授与機関 |
|
|
|
学位授与機関名 |
総合研究大学院大学 |
| 学位名 |
|
|
学位名 |
博士（理学） |
| 学位記番号 |
|
|
内容記述タイプ |
Other |
|
内容記述 |
総研大甲第790号 |
| 研究科 |
|
|
値 |
先導科学研究科 |
| 専攻 |
|
|
値 |
22 光科学専攻 |
| 学位授与年月日 |
|
|
学位授与年月日 |
2004-03-24 |
| 学位授与年度 |
|
|
値 |
2003 |
| 要旨 |
|
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内容記述タイプ |
Other |
|
内容記述 |
In this thesis, we analyze the security of the Bennett 1992 quantum key-distribution protocol (B92 protocol) over a realistic channel assuming that bit values are encoded in single photon polarization states.<br /> First, we study the security of the B92 protocol against individual attack. In the individual attack, eavesdropper (Eve) interacts a qubit emitted by the sender (Alice) with her probe system followed by a measurement on each probe. To make our analysis simple, we propose a modified B92 protocol. Using this protocol, Alice and the receiver (Bob) can estimate Eve's information gain as a function of a few parameters that reflect the imperfections of devices or Eve's disturbance. We find a counter-intuitive behavior of Eve's maximum information gain, i.e., it decreases as the amount of disturbances increases. We also estimate the secret key gain that is the net growth of the secret key per one pulse. We show the region where the modified B92 protocol over a realistic channel is secure against individual attack.<br /> Next, we study the unconditional security of the B92 protocol, which is the security against any attack. To prove the security, we first propose a protocol that is unconditionally secure and can be reduced to the B92 protocol. This protocol employs the entanglement distillation protocol (EDP) based on a filtering operation and the Calderbank-Shor-Steane (CSS) quantum error correcting codes. The bit errors and the phase errors, which have to be estimated for the EDP based on the CSS codes, are correlated after the filtering operation, and we can bound the amount of phase errors from the observed bit errors by an estimation method involving nonorthogonal measurements. The angle between the two states shows a trade-off between accuracy of the estimation and robustness to noises. We show a way to run the unconditionally secure B92. |
| 所蔵 |
|
|
値 |
有 |
要旨・審査要旨 / Abstract, Screening Result (143.3 kB)
