Hanzhi Liu

Ph.D. Student in Computer Science and Co-founder of Nubit

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I am a Ph.D. student at University of California, Santa Barbara, advised by Yu Feng. My research focuses on blockchain infrastructure, formal verification, and zero-knowledge proofs. I co-founded Nubit, where we build Bitcoin infrastructure and security tools.

Education

University of California, Santa Barbara2023–

Ph.D. in Computer Science

Advisor: Yu Feng

Shanghai Jiao Tong University2019–2023

B.Eng. in Electrical Engineering and Computer Science

Advisor: Qinxiang Cao

Talks

Publications

  1. Junrui Liu, Jiaxin Song, Yanning Chen, Hanzhi Liu, Hongbo Wen, Luke Pearson, Yanju Chen, Yu Feng. Tabby: A Synthesis‑Aided Compiler for High‑Performance Zero‑Knowledge Proof Circuits. In OOPSLA 2025.

  2. Hongbo Wen, Hanzhi Liu, Jiaxin Song, Yanju Chen, Wenbo Guo, Yu Feng. FORAY: Towards Effective Attack Synthesis against Deep Logical Vulnerabilities in DeFi Protocols. In CCS 2024. [code]

  3. Junrui Liu, Hanzhi Liu, Ian Kretz, Bryan Tan, Jonathan Wang, Yi Sun, Luke Pearson, Anders Miltner, Isil Dillig, Yu Feng. Certifying Zero‑Knowledge Circuits with Refinement Types. In IEEE S&P 2024. [code]

  4. Lingyun Zhou, Kaiwei Wu, Hanzhi Liu, Yuanning Gao, Xiaofeng Gao. CIRD‑F: Spread and Influence of COVID‑19 in China. Journal of Shanghai Jiaotong University (Science) 25 (2), 147‑156, 2020.

Manuscripts

  1. Hongbo Wen, Hanzhi Liu, Jingyu Ke, Yanju Chen, Dahlia Malkhi, Yu Feng. Thunderbolt: A Formally Verified Protocol for Off‑Chain Bitcoin Transfers. Cryptology ePrint Archive, 2025.

  2. Hanzhi Liu, Jingyu Ke, Hongbo Wen, Luke Pearson, Robin Linus, Lukas George, Manish Bista, Hakan Karakuş, Domo, Junrui Liu, Yanju Chen, Yu Feng. Programmable Bitcoin Verification via Synthesis‑Aided Lifting. Cryptology ePrint Archive, 2024. [code]

  3. Hongbo Wen, Hanzhi Liu, Shuyang Tang, Tianyue Li, Shuhan Cao, Domo, Yanju Chen, Yu Feng. Stateless and Verifiable Execution Layer for Meta‑Protocols on Bitcoin. Cryptology ePrint Archive, 2024.

Bug Finder

Throughout my academic research in formal verification and zero-knowledge systems, I've identified critical vulnerabilities in various blockchain and cryptographic implementations. I also created challenges for CTF competitions, including the Tornado Crash challenge for BlazCTF 2023 (solution). View all reported bugs →

Awards

Every secure system begins as a doubt. We sharpen the doubt into an adversary,
bind it with an invariant, and leave behind, not certainty,
but a contract the world can check.