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Private Quantum Channels and the Cost of Randomizing Quantum Information

Michele Mosca·Alain Tapp·Ronald de Wolf
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Abstract

We investigate how a classical private key can be used by two players, connected by an insecure one-way quantum channel, to perform private communication of quantum information. In particular we show that in order to transmit n qubits privately, 2n bits of shared private key are necessary and sufficient. This result may be viewed as the quantum analogue of the classical one-time pad encryption scheme. From the point of view of the eavesdropper, this encryption process can be seen as a randomization of the original state. We thus also obtain strict bounds on the amount of entropy necessary for randomizing n qubits.

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Michele Mosca, Alain Tapp, Ronald de Wolf. 2000-03-27. Private Quantum Channels and the Cost of Randomizing Quantum Information. https://arxiv.org/abs/quant-ph/0003101

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