Quantum register poisoning attacks
Hiroo Azuma · arXiv (Cornell University) · 2017
We investigate how to attack the quantum computer. We assume that the quantum computer is installed in a research institute and connected to external quantum networks located outside the institute. We show that an attacker can steal an exact solution of a quantum algorithm outside the institute if he replaces an initialized quantum register of the quantum computer with entangled qubits. The replaced register is entangled with qubits the attacker holds. He can apply arbitrary local operations to his own qubits. Moreover, we assume that there is an unauthorized person who helps the attacker to commit a crime inside the institute. He tells garbage data obtained from measurements of the quantum register to the attacker secretly behind a legitimate user's back. If the attacker succeeds in cracking the quantum algorithm, the legitimate user obtains a random result as a solution and does not notice the attacker's illegal acts. We discuss methods for cracking the Deutsch-Jozsa algorithm, Simon's algorithm, and Grover's algorithm. Our method for Grover's algorithm is effective only for a two-qubit register.