(TechnologyReview) How might malicious actors attack such a quantum internet? Neil Johnson at George Washington University in Washington, DC, and a few colleagues have worked out how quantum terrorists could bring the quantum internet to its knees almost instantly and without revealing their identity. More worrying still is that there is no obvious way to counter this new kind of attack.
Johnson and colleagues showed that if several attackers inject their quantum information into the network at the same instant, they can disrupt the global quantum state. In that case the initial state of the system cannot be retrieved, even in principle. Their shocking conclusion is that it requires only three or more quantum terrorists working in unison to inflict maximal disruption on the global quantum state in such systems.
Quantum terrorism is a new threat. Significantly more work will be needed to fully understand the threat and how to mitigate it. As Johnson and his team put it: “Countering this threat properly will require a new understanding of time-dependent quantum correlations in many-body light-matter systems.”