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arXiv quant-ph/0509169quant-ph
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量子加密方案的最优性

On the Optimality of Quantum Encryption Schemes

Iordanis Kerenidis, Daniel Nagaj

摘要:

众所周知,n比特的熵是必要的,并且足以完美地加密n比特(一次一密)。即使我们允许加密是近似的,所需的熵的量也不会渐进地改变。然而,当我们加密量子比特时,情况并非如此。对于n个量子比特的完美加密,2n个比特的熵是必要的和足够的(量子一次一密),但对于近似加密,渐进地只需要n个比特的熵。在本文中,我们提供了最佳的折衷之间的近似测度和经典熵的数量用于加密的单量子比特。然后,我们考虑了n量子比特加密方案,这是一个独立的单量子比特的组合,并提供了在2-和运营商范数的最佳方案。此外,我们还给出了一个反例,证明了基于小偏置集的Ambainis-Smith加密方案在算子范数下不起作用。

英文摘要:

It is well known that n bits of entropy are necessary and sufficient to perfectly encrypt n bits (one-time pad). Even if we allow the encryption to be approximate, the amount of entropy needed doesn't asymptotically change. However, this is not the case when we are encrypting quantum bits. For the perfect encryption of n quantum bits, 2n bits of entropy are necessary and sufficient (quantum one-time pad), but for approximate encryption one asymptotically needs only n bits of entropy. In this paper, we provide the optimal trade-off between the approximation measure epsilon and the amount of classical entropy used in the encryption of single quantum bits. Then, we consider n-qubit encryption schemes which are a composition of independent single-qubit ones and provide the optimal schemes both in the 2- and the operator-norm. Moreover, we provide a counterexample to show that the encryption scheme of Ambainis-Smith based on small-bias sets does not work in the operator-norm.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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