Secure quantum network coding for controlled repeater networks

Tao Shang, Jiao Li, Zhuang Pei +1 more

Tao Shang, Jianwei Liu

Adrian Harkness, Walter O. Krawec, Bing Wang

Abstract Quantum Key Distribution allows two parties to establish a secret key that is secure against computationally unbounded adversaries. To extend the distance between parties, quantum networks are vital. Typically, security in such scenarios assumes the absolute worst case: namely, an adversary has complete control over all repeaters and fiber links in a network and is able to replace them with perfect devices, thus allowing her to hide her attack within the expected natural noise. In a large-scale network, however, such a powerful attack may be infeasible. In this paper, we analyze the case where the adversary can only corrupt a subset of the repeater network connecting Alice and Bob, while some portion of the network near Alice and Bob may be considered safe from attack (though still noisy). We derive a rigorous finite key proof of security assuming this attack model, and show that improved performance and noise tolerances are possible. Our proof methods may be useful to other researchers investigating partially corrupted quantum networks, and our main result may be beneficial to future network operators.

Adrian Harkness, Walter O. Krawec, Bing Wang

Quantum Key Distribution allows two parties to establish a secret key that is secure against computationally unbounded adversaries. To extend the distance between parties, quantum networks, and in particular repeater chains, are vital. Typically, security in such scenarios assumes the absolute worst case: namely, an adversary has complete control over all repeaters and fiber links in a network and is able to replace them with perfect devices, thus allowing her to hide her attack within the expected natural noise. In a large-scale network, however, such a powerful attack may be infeasible. In this paper, we analyze the case where the adversary can only corrupt a contiguous subset of a repeater chain connecting Alice and Bob, while some portion of the network near Alice and Bob may be considered safe from attack (though still noisy). We derive a rigorous finite key proof of security assuming this attack model and show that improved performance and noise tolerances are possible.

Tao Shang, Xiaojie Zhao, Jianwei Liu

This letter proposes new quantum network coding schemes based on controlled teleportation to control the decoding process of receivers in a butterfly network. Firstly, a quantum network coding scheme with two controllers is proposed based on the paradigm XQQ (crossing two qubits) protocol. Then the other scheme based on the perfect quantum network coding protocol with prior entanglement is designed for high fidelity. By introducing the controller, our schemes realize that the decoding process of unicast stream can be controlled, which is helpful to extend these schemes to a general network with unicast or multicast. Our schemes also provide a convenient model to combine authentication into quantum network and would be significant to enhance the security of quantum communication.

Tao Shang, Jianwei Liu