Student(s): Vincent Langford
Project: CLOAQ: Combined Logic and Angle Obfuscation for Quantum Circuits
Advisor(s): Yuntao Liu
Abstract
As quantum computing continues to advance, protecting quantum circuit intellectual property has become a critical challenge in the presence of untrusted quantum compilers. Our work presents an approach to quantum circuit security by combining insights from Quantum Logic Locking and CLOAQ (Combined Logic and Angle Obfuscation for Quantum Circuits).
Quantum Logic Locking introduces a method of embedding multiple key bits into a quantum circuit through controlled gate insertions, ensuring that correct functionality is achieved only when the proper key is applied. This enables an effective mechanism for concealing circuit behavior while maintaining high fidelity and minimal performance degradation.
Complementing this, CLOAQ enhances quantum circuit obfuscation by integrating logic locking with phase angle obfuscation. By leveraging the synergy between these two techniques, CLOAQ significantly improves resilience against reverse engineering and unauthorized access. Evaluation using uniformly sampled quantum states demonstrates stronger security guarantees and greater functional disruption under incorrect keys compared to the prior approach.
While these results demonstrate strong protection with high recoverability, ongoing work focuses on optimizing the cost and overhead of the locking methodology. In particular, we aim to reduce gate count and circuit depth introduced during obfuscation, as well as mitigate compiler constraints that limit optimization. These improvements are essential for enabling practical deployment on quantum hardware, where efficiency and noise sensitivity remain key limitations.
About Vincent Langford
Major: Electrical and Computer Engineering
Vincent Langford is a senior Computer Engineering student at Lehigh University with a strong interest in computer hardware and the semiconductor technologies that enable modern computing systems. Since November 2024, he has conducted research under Professor Yuntao Liu on quantum logic locking and exploring methods to protect quantum circuits from reverse engineering. His work addresses growing security concerns in quantum computing, where untrusted compilers may expose sensitive circuit designs and intellectual property. By investigating secure obfuscation techniques, he aims to contribute to the development of trustworthy quantum computing systems. His interest in research was sparked after being introduced to this opportunity by his advisor, where the challenge of quantum computing obfuscation stood out as particularly compelling. He is motivated by the intersection of theoretical innovation and practical hardware security in next-generation computing systems.