Zhicheng Zhang

Final remark:

Since the threat comes from violating a Bell-type inequality (specifically, Mermin inequality), it has a purely quantum nature:

(a) It makes no computational assumption
(b) It doesn't come from additional communication channel, as entanglement can't transmit information.

5/5

While the scenario is specific, it reveals a threat from quantum entanglement to access control, showing existing models are insufficient.

To protect against the threat, we design new quantum access control models, and analyze their security, flexibility and efficiency.

4/5

We show the answer is likely *no*.

Intuition:

Access control governs how users are allowed to access resources. If a system's security relies on a Bell-type inequality, and the access control mechanism allows users to test it, then introducing quantum resources can cause a security breach.

3/5

Motivation:

You trust a classical computer system, as its access control mechanism is *proven* to protect your private information. One day, the system upgrades by integrating quantum computing services. Should you still trust this system?

2/5

Access Control Threatened by Quantum Entanglement Access control is a cornerstone of computer security that prevents unauthorised access to resources. In this paper, we study access control in quantum computer systems. We present the first explicit s...

New paper with Mingsheng Ying on Quantum Access Control is out:

arxiv.org/abs/2507.02622

Access control is a cornerstone of computer security. We show a classically secure access control system can be insecure when adapted to the quantum setting. The source of the threat is *Entanglement*.

1/5

Quantum Register Machine: Efficient Implementation of Quantum Recursive Programs Quantum recursive programming has been recently introduced for describing sophisticated and complicated quantum algorithms in a compact and elegant way. However, implementation of quantum recursion in...

(b) "Quantum Register Machine: Efficient Implementation of Quantum Recursive Programs" (arxiv.org/abs/2408.10054)

(4/4)

Verification of Recursively Defined Quantum Circuits Recursive techniques have recently been introduced into quantum programming so that a variety of large quantum circuits and algorithms can be elegantly and economically programmed. In this paper, we p...

It's based on the following two joint works with Mingsheng Ying. I'll also present paper (b) at PLDI 2025 in June.

(a) "Verification of Recursively Defined Quantum Circuits" (arxiv.org/abs/2404.05934)

(3/4)

Content:
- Quantum & PL background
- Syntax & Semantics of RQC++, a quantum recursive programming language
- Various examples
- A theoretical framework for efficiently implementing quantum recursive programs

(2/4)

Quantum recursive programs - YouTube Talks given at DIMACS, Rutgers University during April and May 2025 by Zhicheng Zhang, a PhD student at University of Technology Sydney

Excited to share my 5-lecture mini-course 🎬 on "Quantum Recursive Programming"! An elegant way to program complicated quantum algorithms ⚛️

*No prior QC or PL knowledge is needed!

Given during my visit to DIMACS at Rutgers University.

(www.youtube.com/playlist?lis...)

(1/4)

Thanks a lot Clément for this post!

Can I be added please? Thanks!