Arrazola Juan Miguel, Scarani Valerio
Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore.
Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.
Phys Rev Lett. 2016 Dec 16;117(25):250503. doi: 10.1103/PhysRevLett.117.250503. Epub 2016 Dec 15.
We extend covert communication to the quantum regime by showing that covert quantum communication is possible over optical channels with noise arising either from the environment or from the sender's lab. In particular, we show that sequences of qubits can be transmitted covertly by using both a single photon and a coherent state encoding. We study the possibility of performing covert quantum key distribution (QKD) and show that positive key rates and covertness can be achieved simultaneously. Covert communication requires a secret key between the sender and receiver, which raises the problem of how this key can be regenerated covertly. We show that covert QKD consumes more secret bits than it can generate and propose instead a hybrid protocol for covert key regeneration that uses pseudorandom number generators (PRNGs) together with covert QKD to regenerate secret keys. The security of the new key is guaranteed by QKD while the security of the covert communication is at least as strong as the security of the PRNG.
我们通过证明在存在环境噪声或发送方实验室噪声的光信道上进行隐蔽量子通信是可行的，从而将隐蔽通信扩展到量子领域。具体而言，我们表明可以通过使用单光子和相干态编码来隐蔽地传输量子比特序列。我们研究了执行隐蔽量子密钥分发（QKD）的可能性，并表明可以同时实现正的密钥率和隐蔽性。隐蔽通信需要发送方和接收方之间有一个秘密密钥，这就引出了如何隐蔽地再生此密钥的问题。我们表明，隐蔽QKD消耗的秘密比特比其能够生成的更多，因此我们提出了一种用于隐蔽密钥再生的混合协议，该协议使用伪随机数生成器（PRNG）与隐蔽QKD一起再生秘密密钥。新密钥的安全性由QKD保证，而隐蔽通信的安全性至少与PRNG的安全性一样强。
