Beating the PNS attack in practical quantum cryptography
Beating the PNS attack in practical quantum cryptography
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发表时间：
2004
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通讯作者：
Xiang-Bin Wang
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作者：
Xiang-Bin Wang
在实际的量子密钥分配中，通常使用弱相干态，并且信道的透过率可以很小，因此在光子数分裂攻击下协议是完全不安全的。我们提出了一种有效的方法来验证的分数的上限多光子脉冲和下限的分数的单光子脉冲传输到从爱丽丝到鲍勃，无论夏娃的行动类型。该协议简单地使用两个相干态的信号脉冲和真空诱饵。我们验证的上限是足够紧的QKD与非常有损信道，在渐近和非渐近的情况下。平均光子数为0.2 ~ 0.5的相干态可用于实际的量子密码学。与经典密码学不同，量子密钥分发（QKD）[1-3]可以通过不可克隆定理[4]帮助两个远程方建立安全密钥。此外，噪声信道上的无条件安全性的证明已经给出[5-8]。弱相干态量子密钥分配的安全性也得到了证明[9，12]。然而，量子密钥分配在实际应用中仍然存在一些限制，特别是在长距离上。特别是，大的信道损耗似乎是长距离弱相干态量子密钥分配的主要挑战。一种退相相干态|μe实际上是Email地址的混合状态：wang@qci.jst.go.jp
In practical quantum key distribution, weak coherent state is often used and the channel transmittance can be very small therefore the protocol could be totally insecure under the photon-number-splitting attack. We propose an efficient method to verify the upper bound of the fraction of multi-photon pluses and the lower bound of the fraction of single-photon pulses transmitted to from Alice to Bob, given whatever type of Eve’s action. The protocol simply uses two coherent states for the signal pulses and vacuum for decoy. Our verified upper bound is sufficiently tight for QKD with very lossy channel, in both asymptotic case and non-asymptotic. The coherent states with mean photon number from 0.2 to 0.5 can be used in practical quantum cryptography. Unlike the classical cryptography, quantum key distribution(QKD) [1–3] can help two remote parties to set up the secure key by non-cloning theorem [4]. Further, proofs for the unconditional security over noisy channel have been given [5–8]. The security of practical QKD with weak coherent states has also been shown [9,12]. However there are still some limitations for QKD in practice, especially over long distance. In particular, large loss of channel seems to be the main challenge to the long-distance QKD with weak coherent states. A dephased coherent state |μe〉 is actually a mixed state of Email address: wang@qci.jst.go.jp