  The ability for users to access quantum computers through the cloud has
increased rapidly in recent years. Despite still being Noisy Intermediate-Scale
Quantum (NISQ) machines, modern quantum computers are now being actively
employed for research and by numerous startups. Quantum algorithms typically
produce probabilistic results, necessitating repeated execution to produce the
desired outcomes. In order for the execution to begin from the specified ground
state each time and for the results of the prior execution not to interfere
with the results of the subsequent execution, the reset mechanism must be
performed between each iteration to effectively reset the qubits. However, due
to noise and errors in quantum computers and specifically these reset
mechanisms, a noisy reset operation may lead to systematic errors in the
overall computation, as well as potential security and privacy vulnerabilities
of information leakage. To counter this issue, we thoroughly examine the state
leakage problem in quantum computing, and then propose a solution by employing
the classical and quantum one-time pads before the reset mechanism to prevent
the state leakage, which works by randomly applying simple gates for each
execution of the circuit. In addition, this work explores conditions under
which the classical one-time pad, which uses fewer resources, is sufficient to
protect state leakage. Finally, we study the role of various errors in state
leakage, by evaluating the degrees of leakage under different error levels of
gate, measurement, and sampling errors. Our findings offer new perspectives on
the design of reset mechanisms and secure quantum computing systems.
