This paper introduces ObfusQate, a novel tool that conducts obfuscations using quantum primitives to enhance the security of both classical and quantum programs. We have designed and implemented two primary categories of obfuscations: quantum circuit level obfuscation and code level obfuscation, encompassing a total of eight distinct methods. Quantum circuit-level obfuscation leverages on quantum gates and circuits, utilizing strategies such as quantum gate hiding and identity matrices to construct complex, non-intuitive circuits that effectively obscure core functionalities and resist reverse engineering, making the underlying code difficult to interpret. Meanwhile, code-level obfuscation manipulates the logical sequence of program operations through quantum-based opaque predicates, obfuscating execution paths and rendering program behavior more unpredictable and challenging to analyze. Additionally, ObfusQate can be used to obfuscate malicious code segments, making them harder to detect and analyze. These advancements establish a foundational framework for further exploration into the potential and limitations of quantum-based obfuscation techniques, positioning ObfusQate as a valuable tool for future developers to enhance code security in the evolving landscape of software development. To the best of our knowledge, ObfusQate represents the pioneering work in developing an automated framework for implementing obfuscations leveraging quantum primitives. Security evaluations show that obfuscations by ObfusQate maintain code behavior with polynomial overheads in space and time complexities. We have also demonstrated an offensive use case by embedding a keylogger into Shor's algorithm and obfuscating it using ObfusQate. Our results show that current Large language models like GPT 4o, GPT o3 mini and Grok 3 were not able to identify the malicious keylogger after obfuscation.
This paper introduces ObfusQate, a novel tool that conducts obfuscations using quantum primitives to enhance the security of both classical and quantum programs. We have designed and implemented two primary categories of obfuscations: quantum circuit level obfuscation and code level obfuscation, encompassing a total of eight distinct methods. Quantum circuit-level obfuscation leverages on quantum gates and circuits, utilizing strategies such as quantum gate hiding and identity matrices to construct complex, non-intuitive circuits that effectively obscure core functionalities and resist reverse engineering, making the underlying code difficult to interpret. Meanwhile, code-level obfuscation manipulates the logical sequence of program operations through quantum-based opaque predicates, obfuscating execution paths and rendering program behavior more unpredictable and challenging to analyze. Additionally, ObfusQate can be used to obfuscate malicious code segments, making them harder to detect and analyze. These advancements establish a foundational framework for further exploration into the potential and limitations of quantum-based obfuscation techniques, positioning ObfusQate as a valuable tool for future developers to enhance code security in the evolving landscape of software development. To the best of our knowledge, ObfusQate represents the pioneering work in developing an automated framework for implementing obfuscations leveraging quantum primitives. Security evaluations show that obfuscations by ObfusQate maintain code behavior with polynomial overheads in space and time complexities. We have also demonstrated an offensive use case by embedding a keylogger into Shor's algorithm and obfuscating it using ObfusQate. Our results show that current Large language models like GPT 4o, GPT o3 mini and Grok 3 were not able to identify the malicious keylogger after obfuscation.
We introduce ObfusQate, a novel framework that performs software obfuscation using quantum primitives to enhance the security of both classical and quantum programs. ObfusQate implements eight obfuscation techniques categorized into quantum circuit-level and code-level transformations. Circuit-level obfuscation leverages quantum gates, identity operations, and unitary transformations to construct non-intuitive circuits that resist reverse engineering. Code-level obfuscation employs quantum-based opaque predicates to obscure control flow, making execution paths unpredictable. We evaluate the effectiveness of ObfusQate using three benchmark quantum algorithms: Bernstein-Vazirani, Shor’s, and QAOA. Experiments show that the framework incurs tunable polynomial overhead in both time and space, while preserving functional correctness. Additionally, we demonstrate an offensive use case by embedding a keylogger into Shor’s algorithm. Large language models (GPT-4o, GPT-o3-mini, and Grok-3) successfully identified the payload in the unobfuscated version, but failed when it was obfuscated using ObfusQate. To our knowledge, ObfusQate is the first automated system for quantum software obfuscation. It provides a foundation for secure deployment of quantum software in adversarial and shared environments.
A major unresolved question in quantum cryptography is whether it is possible to obfuscate arbitrary quantum computation. Indeed, there is much yet to understand about the feasibility of quantum obfuscation even in the classical oracle model, where one is given for free the ability to obfuscate any classical circuit. In this work, we develop a new array of techniques that we use to construct a quantum state obfuscator, a powerful notion formalized recently by Coladangelo and Gunn (arXiv:2311.07794) in their pursuit of better software copy-protection schemes. Quantum state obfuscation refers to the task of compiling a quantum program, consisting of a quantum circuit C with a classical description and an auxiliary quantum state ψ, into a functionally-equivalent obfuscated quantum program that hides as much as possible about C and ψ. We prove the security of our obfuscator when applied to any pseudo-deterministic quantum program, i.e. one that computes a (nearly) deterministic classical input / classical output functionality. Our security proof is with respect to an efficient classical oracle, which may be heuristically instantiated using quantum-secure indistinguishability obfuscation for classical circuits. Our result improves upon the recent work of Bartusek, Kitagawa, Nishimaki and Yamakawa (STOC 2023) who also showed how to obfuscate pseudo-deterministic quantum circuits in the classical oracle model, but only ones with a completely classical description. Furthermore, our result answers a question of Coladangelo and Gunn, who provide a construction of quantum state indistinguishability obfuscation with respect to a quantum oracle, but leave the existence of a concrete real-world candidate as an open problem. Indeed, our quantum state obfuscator together with Coladangelo-Gunn gives the first candidate realization of a “best-possible” copy-protection scheme for all polynomial-time functionalities. Our techniques deviate significantly from previous works on quantum obfuscation. We develop several novel technical tools which we expect to be broadly useful in quantum cryptography. These tools include a publicly-verifiable, linearly-homomorphic quantum authentication scheme with classically-decodable ZX measurements (which we build from coset states), and a method for compiling any quantum circuit into a ”linear + measurement” () quantum program: an alternating sequence of CNOT operations and partial ZX measurements.
Program obfuscation aims to hide the inner workings of a program while preserving its functionality. In the quantum setting, recent works have obtained obfuscation schemes for specialized classes of quantum circuits. For instance, Bartusek, Brakerski, and Vaikuntanathan (STOC 2024) constructed a quantum state obfuscation scheme, which supports the obfuscation of quantum programs represented as quantum states for pseudo-deterministic quantum programs with classical inputs and outputs in the classical oracle model. In this work, we improve upon existing results by constructing the first quantum state obfuscation scheme for unitary (or approximately unitary) quantum programs supporting quantum inputs and outputs in the classical oracle model. At the core of our obfuscation scheme are two novel ingredients: a functional quantum authentication scheme that allows key holders to learn specific functions of the authenticated quantum state with simulationbased security, and a compiler that represents an arbitrary quantum circuit as a projective linear-plus-measurement quantum program described by a sequence of non-adaptive Clifford gates interleaved with adaptive and compatible measurements.
Optimization of quantum circuits using an efficient compiler is key to its success for NISQ computers. Several 3rd party compilers are evolving to offer improved performance for large quantum circuits. These 3rd parties, or just a certain release of an otherwise trustworthy compiler, may possibly be untrusted and this could lead to an adversary to Reverse Engineer (RE) the quantum circuit for extracting sensitive aspects e.g., circuit topology, program, and its properties. In this paper, we propose obfuscation of quantum circuits to hide the functionality. Quantum circuits have inherent margin between correct and incorrect outputs. Therefore, obfuscation (i.e., corruption of functionality) by inserting dummy gates is nontrivial. We insert dummy SWAP gates one at a time for maximum corruption of functionality before sending the quantum circuit to an untrusted compiler. If an untrusted party clones the design, they get incorrect functionality. The designer removes the dummy SWAP gate post-compilation to restore the correct functionality. Compared to a classical counterpart, the quantum chip does not reveal the circuit functionality. Therefore, an adversary cannot guess the SWAP gate and location/validate using an oracle model. Evaluation of realistic quantum circuit with/without SWAP insertion is impossible in classical computers. Therefore, we propose a metric-based SWAP gate insertion process. The objective of the metric is to ensure maximum corruption of functionality measured using Total Variation Distance (TVD). The proposed approach is validated using IBM default noisy simulation model. Our metric-based approach predicts the SWAP position to achieve TVD of upto 50%, and performs 7.5% better than average TVD, and performs within 12.3% of the best obtainable TVD for the benchmarks. We obtain an overhead of < 5% for the number of gates and circuit depth after SWAP addition.
Quantum computing often requires classical data to be supplied to execution environments that may not be fully trusted or isolated. While encryption protects data at rest and in transit, it provides limited protection once computation begins, when classical values are encoded into quantum registers. This paper explores data obfuscation for protecting classical values during quantum computation. To the best of our knowledge, we present the first explicit data obfuscation technique designed to protect classical values during quantum execution. We propose an obfuscation technique that encodes sensitive data into structured quantum representations across multiple registers, avoiding direct exposure while preserving computational usability. Reversible quantum operations and amplitude amplification allow selective recovery of valid encodings without revealing the underlying data. We evaluate the feasibility of the proposed method through simulation and analyze its resource requirements and practical limitations. Our results highlight data obfuscation as a complementary security primitive for quantum computing.
Quantum circuit obfuscation is becoming increasingly important to prevent theft and reverse engineering of quantum algorithms. As quantum computing advances, the need to protect the intellectual property contained in quantum circuits continues to grow. Existing methods often provide limited defense against structural and statistical analysis or introduce considerable overhead. In this paper, we propose a novel quantum obfuscation method that uses randomized U3 transformations to conceal circuit structure while preserving functionality. We implement and assess our approach on QASM circuits using Qiskit AER, achieving over 93\% semantic accuracy with minimal runtime overhead. The method demonstrates strong resistance to reverse engineering and structural inference, making it a practical and effective approach for quantum software protection.