Yu Feng

Yu Feng

Associate Professor

UC Santa Barbara

I am an associate professor in the computer science department at UC Santa Barbara. I received my Ph.D. from UT Austin in 2018, where I was advised by Isil Dillig. My group builds automated reasoning tools at the intersection of programming languages, formal verification, and security — with recent focus on zero-knowledge proof systems and safe AI agents. Our work has been recognized with multiple Distinguished/Best Paper Awards at PLDI, CHI, and ASE, and has been supported by NSF, DARPA, Google, and the Ethereum Foundation.

My research develops principled techniques — rooted in program synthesis, type theory, and constraint solving — to automatically build, verify, and secure software systems. Current focus areas include: (1) formal methods and security for AI agents, ensuring autonomous systems behave safely and correctly through verification and runtime guarantees; (2) compilers and verifiers for zero-knowledge proof circuits, where we have built tools like Tabby and Tessel that detect vulnerabilities and optimize performance in ZK systems deployed in production; (3) smart contract and DeFi security, including attack synthesis and state-inconsistency detection; and (4) synthesis-driven tools for end-user programming, such as data visualization and code transpilation. A unifying theme is combining logical reasoning with learning to push the frontier of what automated tools can guarantee.

Research Interests

  • AI Agent Safety & Verification
  • Zero-Knowledge Proofs
  • Program Synthesis
  • Programming Languages
  • Security

Education

Ph.D. in Computer Science, 2018
University of Texas at Austin
M.S. in Computer Science, 2008
Beihang University

Students

Hanzhi Liu
PhD

Publications

2025
Tabby: A Synthesis-Aided Compiler for High-Performance Zero-Knowledge Proof Circuits
Junrui Liu, Jiaxin Song, Yanning Chen, Hanzhi Liu, Hongbo Wen, Luke Pearson, Yanju Chen, Yu Feng
OOPSLA, 2025
Automated Repair of OpenID Connect Programs
Tamjid Al Rahat, Yanju Chen, Yu Feng, Yuan Tian
ASE, 2025
Tessel: An Optimizing Compiler for Efficient Zero-Knowledge Circuits
Junrui Liu, Jiaxin Song, Yanning Chen, Hanzhi Liu, Hongbo Wen, Yanju Chen, Yu Feng
SBC, 2025
2024
FORAY: Towards Effective Attack Synthesis against Deep Logical Vulnerabilities in DeFi Protocols
Hongbo Wen, Hanzhi Liu, Jiaxin Song, Yanju Chen, Wenbo Guo, Yu Feng
CCS, 2024
AuthSaber: Automated Safety Verification of OpenID Connect Programs
Tamjid Al Rahat, Yu Feng, Yuan Tian
CCS, 2024
Refinement Types for Visualization
Junrui Liu, Jingtao Xia, Nicholas Brown, Yanju Chen, Yu Feng
ASE, 2024
Certifying Zero-Knowledge Circuits with Refinement Types
Junrui Liu, Hanzhi Liu, Ian Kretz, Bryan Tan, Jonathan Wang, Yi Sun, Luke Pearson, Anders Miltner, Isil Dillig, Yu Feng
IEEE Security & Privacy (Oakland), 2024
Practical Security Analysis of Zero-Knowledge Proof Circuits
Hongbo Wen, Jon Stephens, Yanju Chen, Kostas Ferles, Shankara Pailoor, Kyle Charbonnet, Isil Dillig, Yu Feng
USENIX Security, 2024
2023
Fast and Reliable Program Synthesis via User Interaction
Yanju Chen, Chenglong Wang, Xinyu Wang, Osbert Bastani, Yu Feng
ASE, 2023
Conflict-Driven Synthesis for Layout Engines
Junrui Liu, Yanju Chen, Eric Atkinson, Yu Feng, Ras Bodik
PLDI, 2023
Automated Detection of Under-constrained Circuits in Zero-Knowledge Proofs
Yanju Chen, Shankara Pailoor, Franklyn Wang, Clara Rodríguez, Jacob Van Geffen, Jason Morton, Michael Chu, Brian Gu, Yu Feng, Isil Dillig
PLDI, 2023
2022
Learning Contract Invariants Using Reinforcement Learning
Junrui Liu, Yanju Chen, Bryan Tan, Isil Dillig, Yu Feng
ASE, 2022
Cerberus: Query-driven Scalable Security Checking for OAuth Service Provider Implementations
Tamjid Al Rahat, Yu Feng, Yuan Tian
CCS, 2022
Visualization Question Answering Using Introspective Program Synthesis
Yanju Chen, Xifeng Yan, Yu Feng
PLDI, 2022 Distinguished Paper Award
Tree Traversal Synthesis Using Domain-Specific Symbolic Compilation
Yanju Chen, Junrui Liu, Yu Feng, Ras Bodik
ASPLOS, 2022
SolType: Refinement Types for Solidity
Bryan Tan, Benjamin Mariano, Shuvendu Lahiri, Isil Dillig, Yu Feng
POPL, 2022
Automated Transpilation of Imperative to Functional Code using Neural-Guided Program Synthesis
Benjamin Mariano, Yanju Chen, Yu Feng, Greg Durrett, Isil Dillig
OOPSLA, 2022
Synthesis-Powered Optimization of Smart Contracts via Data Type Refactoring
Yuepeng Wang, Maruth Goyal, James Dong, Yanju Chen, Yu Feng, Isil Dillig
OOPSLA, 2022
SAILFISH: Vetting Smart Contract State-Inconsistency Bugs in Seconds
Priyanka Bose, Dipanjan Das, Yanju Chen, Yu Feng, Christopher Kruegel, Giovanni Vigna
IEEE Security & Privacy (Oakland), 2022

Awards & Grants

  • Ethereum Academic Award, 2025
  • Ethereum Academic Award, 2024
  • Ethereum Academic Award, 2023
  • ACM SIGPLAN Distinguished Paper Award, PLDI 2022
  • ACM SIGCHI Best Paper Award, CHI 2021
  • Google Faculty Research Award (Security), 2021
  • ACM SIGSOFT Distinguished Paper Award, ASE 2020
  • DARPA HARDEN, 2022-2025
  • NSF-SaTC (core) medium, 2019-2022
  • ACM SIGPLAN Distinguished Paper Award, PLDI 2018
  • UT Austin Graduate School Dissertation Fellowship, 2018
  • ACM SIGPLAN PAC award, 2017

Service

Program Committee

POPL'27, CCS'26, ISSTA'26, CCS'25, PLDI'25, CCS'24, OOPSLA'24, CCS'23, PLDI'22, ICSE'22, ASPLOS'21, OOPSLA'20, PLDI'20, POPL'20 (ERC), CAV'20, CAV'19, POPL'18 (AEC), ECOOP'18 (AEC), CAV'16 (AEC), MOBILESoft'16 (Publicity Chair), MOBILESoft'15

External Review

POPL'18, CAV'18, TSE'18, POPL'17, OOPSLA'16, PLDI'16, PLDI'15

Contact

Office
Harold Frank Hall, Room 2157, UCSB
GitHub
X / Twitter