Quantum Opacity, Classical Clarity: A Hybrid Approach to Quantum Circuit Obfuscation

TL;DR

This paper introduces a hybrid quantum circuit obfuscation method that inserts quantum gates to protect proprietary designs, ensuring security during untrusted compilation without complex reversals.

Contribution

A novel, compiler-agnostic obfuscation technique using quantum gate insertion and classical correction, enhancing security in quantum circuit compilation.

Findings

Achieves high obfuscation effectiveness with Total Variation Distance above 0.5

Demonstrates consistent negative Degree of Functional Corruption (DFC)

Validated on five benchmark quantum algorithms using IBM Qiskit

Abstract

Quantum computing leverages quantum mechanics to achieve computational advantages over classical hardware, but the use of third-party quantum compilers in the Noisy Intermediate-Scale Quantum (NISQ) era introduces risks of intellectual property (IP) exposure. We address this by proposing a novel obfuscation technique that protects proprietary quantum circuits by inserting additional quantum gates prior to compilation. These gates corrupt the measurement outcomes, which are later corrected through a lightweight classical post-processing step based on the inserted gate structure. Unlike prior methods that rely on complex quantum reversals, barriers, or physical-to-virtual qubit mapping, our approach achieves obfuscation using compiler-agnostic classical correction. We evaluate the technique across five benchmark quantum algorithms -- Shor's, QAOA, Bernstein-Vazirani, Grover's, and HHL -- using IBM's Qiskit framework. The results demonstrate high Total Variation Distance (above 0.5) and consistently negative Degree of Functional Corruption (DFC), confirming both statistical and functional obfuscation. This shows that our method is a practical and effective solution for the security of quantum circuit designs in untrusted compilation flows.