Abstract

Quantum entanglement plays a pivotal role in many communication protocols, like secret sharing and quantum cryptography. We consider a scenario where more than two parties are involved in a protocol and share a multipartite entangled state. In particular, we considered the protocol of Controlled Quantum Key Distribution (CoQKD), introduced in the reference H. Chao, X. Peng, and G. G-Can, Chin. Phys. Lett. 20, 183 (2003), where, two parties, Alice and Bob establish a key with the cooperation of other parties. Other parties control/supervise whether Alice and Bob can establish the key, its security and key rate. We discuss the case of three parties in detail and find suitable resource states. We discuss the controlling power of the third party, Charlie. We also examine the usefulness of the new resource states for generating conference key and for cooperative teleportation. We find that recently introduced Bell inequalities can be useful to establish the security of the conference key. We also generalize the scenario to more than three parties.

Graphical abstract

中文翻译：

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受控量子密钥分配的资源状态结构

摘要

量子纠缠在许多通信协议中起着关键作用，例如秘密共享和量子密码学。我们考虑一种方案，其中协议涉及两个以上的方，并且共享多部分纠缠状态。特别是，我们考虑了在参考文献H. Chao，X. Peng和G. G-Can，Chin中引入的受控量子密钥分发（CoQKD）协议。物理 来吧 20，第183页，（2003年），其中两个当事方爱丽丝（Alice）和鲍勃（Bob）在其他当事方的合作下建立了密钥。其他各方控制/监督Alice和Bob是否可以建立密钥，其安全性和密钥率。我们将详细讨论三方的情况，并找到合适的资源状态。我们讨论了第三方Charlie的控制权。我们还研究了新资源状态对于生成会议密钥和协作远距传送的有用性。我们发现最近引入的贝尔不等式对于建立会议密钥的安全性很有用。我们还将该方案推广到三个以上的参与者。

图形概要