  Quantum computing is a promising paradigm for efficiently solving large and
high-complexity problems. To protect quantum computing privacy, pioneering
research efforts proposed to redefine differential privacy (DP) in quantum
computing, i.e., quantum differential privacy (QDP), and harvest inherent
noises generated by quantum computing to implement QDP. However, such an
implementation approach is limited by the amount of inherent noises, which
makes the privacy budget of the QDP mechanism fixed and uncontrollable. To
address this issue, in this paper, we propose to leverage quantum error
correction (QEC) techniques to reduce quantum computing errors, while tuning
the privacy protection levels in QDP. In short, we gradually decrease the
quantum noise error rate by deciding whether to apply QEC operations on the
gate in a multiple single qubit gates circuit. We have derived a new
calculation formula for the general error rate and corresponding privacy
budgets after QEC operation. Then, we expand to achieve further noise reduction
using multi-level concatenated QEC operation. Through extensive numerical
simulations, we demonstrate that QEC is a feasible way to regulate the degree
of privacy protection in quantum computing.
