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Rick Rujia Li

Rujia (李佳轩, RRL) is a Postdoctoral Fellow, Shuimu Tsinghua Scholar at Institute for Advanced Study, Tsinghua University, Tsinghua University, collaborating with Dr. Sisi Duan. He received his Ph.D. in Computer Science from the University of Birmingham (Joint Program with SUSTech), advised by Dr.David Galindo, Dr.Qi Wang and Prof. Mark Ryan.

Research Interests

His research focuses on Privacy-Preserving Smart Contracts (PPSCs), with a particular emphasis on improving the (economic-level and system-level) security of consensus algorithms and privacy-preserving technologies that underpin the design and implementation of PPSCs.
  • Hybrid consensus algorithm (GHOST + BFT) [1]
  • Hybrid privacy-preserving technology (TEE[2] + cryptographic primitives[3])

Latest News

  • [2025-01] Available Attestation: Towards a Reorg-Resilient Solution for Ethereum Proof-of-Stake is accepted by USENIX Security 2025.
  • [2025-01] Accountable Decryption made Formal and Practical is accepted by IEEE TIFS 2025.
  • [2024-10] Bringing Smart Contract Confidentiality via Trusted Hardware: Fact and Fiction is accepted by IEEE TIFS 2024.
  • [2024-03] Max Attestation Matters: Making Honest Parties Lose Their Incentives in Ethereum PoS is accepted by USENIX Security 2024.
  • [2023-01] Time-manipulation Attack: Breaking Fairness against Proof of Authority Aura is accepted by WWW 2023.
More News
Last updated 05/02/2025, Rujia

Privacy-Preserving Smart Contracts

Privacy-Preserving Smart Contracts (PPSCs) are designed to keep the data and transactions confidential while ensuring the secure execution of transactions on the blockchain. As shown in the diagram below, PPSCs are built on two main components: a consensus algorithm and privacy-preserving technology.


His research focuses on improving the security of consensus algorithms and privacy-preserving technologies that underpin the design and implementation of PPSCs.

Research Areas

Hybrid Consensus Algorithm (GHOST + BFT)

Analyzing vulnerabilities in state-of-the-art hybrid consensus mechanisms and propose enhanced, secure alternatives.

  • 2025 PoSA Attack Analysis (Ongoing Work)
  • 2024 PoS Attack Remediation (USENIX Security'25)
  • 2023 PoS Attack Analysis (USENIX Security'24)
  • 2022 PoA Algorithm Vulnerabilities (WWW'23, ASIACCS'22, ICBC'22)
  • 2021 BFT Attack Framework (ACM DLT'22)
  • 2020 Weak Consensus Algorithm (INFOCOM'21, NDSS Poster'21)

Hybrid Privacy-Preserving Technology (TEE + Cryptography)

Integrating Trusted Execution Environment (TEE) with cryptographic techniques to enhance smart contract privacy.

  • 2025 Enhancing the Security of TEE Attestation (Ongoing Work)
  • 2024 Practical Multi-party Computation using TEE (Ongoing Work)
  • 2023 Secure Blockchain Mempool using TEE (Ongoing Work)
  • 2023 Making Decryption Accountable using TEE (IEEE TIFS'25)
  • 2022 Mechanism of Confidential Smart Contracts (IEEE TIFS'24, PETS'22, ISC'20, CBT'19)

Industry Impact

The outcomes of our PPSCs research have been adopted by some organizations to improve the privacy and security of their products, including but not limited to:

The People’s Bank of China

The People’s Bank of China

State Grid Corporation of China

State Grid Corporation of China

China Mobile

China Mobile

Ant Group

Ant Group

Ethereum Foundation

Ethereum Foundation

Rick Rujia Li Biography

Bachelor
Whu
2009
R&D Eng
SG EPRI
2013
Secure Arch Asst
SG IT
2014
Master
UoB
2016
Intern
UoB IC
2017
PhD
UoB
2018
Team Leader
COCRYPTO
2022
Visiting Scholar
THU
2022
Postdoc
THU
2023

Position

Education

Honours/Certification

  • Oracle Certified Professional, Oracle University (01/2015)
  • Gold Award in Int’l Soft China 2014, National Development and Reform Commission (08/2014)

Publication

The following is a selected list of publications, sorted in reverse chronological order (*equal contribution). For the full list, please visit his Google Scholar.

Selected Papers

  1. Available Attestation: Towards a Reorg-Resilient Solution for Ethereum Proof-of-Stake.
    34th USENIX Security Symposium (USENIX Security 2025), August 2025.
    Mingfei Zhang, Rujia Li, Xueqian Lu, Sisi Duan. [PDF]
  2. Accountable Decryption made Formal and Practical.
    IEEE Transactions on Information Forensics and Security (IEEE TIFS 2025), January 2025.
    Rujia Li, Yuanzhao Li, Qin Wang, Sisi Duan, Qi Wang, Mark Ryan. [PDF]
  3. Bringing Smart Contract Confidentiality via Trusted Hardware: Fact and Fiction.
    IEEE Transactions on Information Forensics and Security (IEEE TIFS 2024), November 2024.
    Rujia Li, Qin Wang, Yuanzhao Li, Sisi Duan, Qi Wang, David Galindo. [PDF]
  4. Max Attestation Matters: Making Honest Parties Lose Their Incentives in Ethereum PoS.
    33rd USENIX Security Symposium (USENIX Security 2024), August 2024.
    Mingfei Zhang, Rujia Li, Sisi Duan. [PDF]
  5. Time-manipulation Attack: Breaking Fairness against Proof of Authority Aura.
    32nd International World Wide Web Conference (WWW 2023), May 2023.
    Xinrui Zhang*, Rujia Li*, Qin Wang, Qi Wang, Sisi Duan. [PDF]
  6. SoK: TEE-assisted Confidential Smart Contract.
    22nd Privacy Enhancing Technologies Symposium (PETS 2022), July 2022.
    Rujia Li*, Qin Wang*, Qi Wang, David Galindo, Mark Ryan. [PDF]
  7. Exploring Unfairness on Proof of Authority: Order Manipulation Attacks and Remedies.
    17th ACM ASIA Conference on Computer and Communications Security (ACM ASIACCS 2022), May 2022.
    Qin Wang*, Rujia Li*, Shiping Chen, Qi Wang, Yang Xiang. [PDF]
  8. A Weak Consensus Algorithm and Its Application to High-Performance Blockchain.
    40th IEEE International Conference on Computer Communications (INFOCOM 2021), May 2021.
    Qin Wang*, Rujia Li*. [PDF]
  9. An Offline Delegatable Cryptocurrency System.
    3rd IEEE International Conference on Blockchain and Cryptocurrency (ICBC 2021), May 2021.
    Rujia Li*, Qin Wang*, Xinrui Zhang, Qi Wang, David Galindo, Yang Xiang. [PDF]
  10. An Accountable Decryption System Based on Privacy-Preserving Smart Contracts.
    23rd Information Security Conference (ISC 2020), December 2020.
    Rujia Li, Qin Wang, Feng Liu, Qi Wang, David Galindo. [PDF]
  11. Auditable Credential Anonymity Revocation Based on Privacy-Preserving Smart Contracts.
    ESORICS 2019, 3rd International Workshop on Cryptocurrencies and Blockchain Technology, September 2019.
    Rujia Li, David Galindo, Qi Wang. [PDF]

Selected Posters

  1. Poster: An Offline Delegatable Cryptocurrency System.
    28th Network and Distributed System Security Symposium (NDSS 2021), February 2021.
    Rujia Li, Qin Wang, Xinrui Zhang, Qi Wang, David Galindo, Yang Xiang. [PDF]
  2. Poster: Transparent Certificate Revocation for CBE Based on Blockchain..
    41st IEEE Symposium on Security and Privacy (SP 2020), February 2021.
    Qin Wang*, Rujia Li*, Qi Wang, David Galindo. [PDF]

Thesis

  1. Design and Evaluation of Blockchain-based Security Protocols.
    PhD thesis 2022 [PDF]
  2. Better Security Over Blockcerts.
    Msc thesis 2017 [PDF]

Service

He is externaly/internally invited to conduct reviews for the following conferences and journals.

Conferences (external reviewer)

Journals

Research Students

He is fortunate to collaborate with these excellent students.

Alumni

Teaching

Teaching assistant (TA) for following courses.

Others

  • President, the Postdoctoral Association at the IAS, Tsinghua University. 11/2023-now
  • Captain, the Postdoctoral Football Club of Tsinghua University. 10/2024-now

Philosophy

  • Less is more
  • A genuine love for knowledge and innovation
  • Don't cry over spilled milk

Research Taste

  • Novelty
  • Potential for significant impact
  • Real-world problems

Slides

Contact

  • Email: cnVqaWEucmVzZWFyY2hAb3V0bG9vay5jb20=
    (please decode using Base64)
  • Address (From 2022 to now):
            Institute for Advanced Study
            Tsinghua University
            Haidian District, 100084, Beijing, China
  • Links: GitHub, Blog, Linkedin