Securing HHL Quantum Algorithm against Quantum Computer Attacks

As the quantum research community expands and new quantum algorithms are created and implemented, it is essential to consider the security implications and potential threats that could lead to the misuse of these algorithms or compromise the information processed by them.

This work focuses on securing the HHL quantum algorithm against quantum computer attacks, specifically two types of potential attacks that could be deployed on a cloud-based quantum computer by an attacker circuit attempting to interfere with a victim circuit: the Improper Initialization Attack (IIA) and the Higher Energy Attack (HEA).

To protect the HHL algorithm from IIA and HEA, new defense strategies need to be employed. This work proposes first-of-a-kind defense strategies against these attacks on the HHL quantum algorithm, including defenses for the ancilla qubit, the clock qubits, and the b qubit.

Additionally, this work demonstrates an implementation of a new quantum circuit for the HHL quantum algorithm. The redesigned quantum circuit is necessary to successfully apply and realize all proposed defense strategies.

Finally, this work illustrates how these defense strategies function in practice, specifically how they can protect the HHL quantum algorithm from both IIA and HEA across multiple qubits involving all three types of qubits used in the HHL algorithms: ancilla, clock, and b.