  In quantum networking, repeater hijacking menaces the security and utility of
quantum applications. To deal with this problem, it is important to take a
measure of the impact of quantum repeater hijacking. First, we quantify the
workload of each quantum repeater with regards to each quantum communication.
Based on this, we show the costs for repeater hijacking detection using
distributed quantum state tomography and the amount of work loss and rerouting
penalties caused by hijacking. This quantitive evaluation covers both
purification-entanglement swapping and quantum error correction repeater
networks. Naive implementation of the checks necessary for correct network
operation can be subverted by a single hijacker to bring down an entire
network. Fortunately, the simple fix of randomly assigned testing can prevent
such an attack.

Quantum Physics