On the Power of Quantum Encryption Keys
On the Power of Quantum Encryption Keys
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DOI：
10.1007/978-3-540-88403-3_12
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发表时间：
2008-08
期刊：
影响因子：
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通讯作者：
Akinori Kawachi;Christopher Portmann
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文献类型：
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作者：
Akinori Kawachi;Christopher Portmann
量子态随机化的标准定义是对以经典秘钥为条件的量子信息进行某种变换。量子态随机化是经典一次性密码的量子模拟。我们研究了这种转换以量子加密密钥状态ρ为条件的加密方案，而不是以经典字符串为条件的加密方案，并将这种对称密钥方案扩展到一个非对称密钥模型，在该模型中，相同的加密密钥ρ的副本可以由几个不同的人持有，但保持信息理论的安全性。我们根据解密密钥的熵找到了在这两种模型中可以安全创建的消息大小和加密密钥副本数的边界，并证明了使用经典加密密钥的方案可以渐近达到最优边界。这意味着，与使用纯经典密钥相比，使用量子态作为加密密钥不允许创建和共享更多的量子态，也不允许加密更大的消息。
The standard definition of quantum state randomization, which is the quantum analog of the classical one-time pad, consists in applying some transformation to the quantum message conditioned on a classical secret keyk. We investigate encryption schemes in which this transformation is conditioned on a quantum encryption key stateρkinstead of a classical string, and extend this symmetric-key scheme to an asymmetric-key model in which copies of the same encryption keyρkmay be held by several different people, but maintaining information-theoretical security. We find bounds on the message size and the number of copies of the encryption key which can be safely created in these two models in terms of the entropy of the decryption key, and show that the optimal bound can be asymptotically reached by a scheme using classical encryption keys. This means that the use of quantum states as encryption keys does not allow more of these to be created and shared, nor encrypt larger messages, than if these keys are purely classical.