Fukang Liu

I am an assistant professor at Tokyo Institute of Technology, and have worked in the area of cryptography since 2017. During this period, I have participated in many interesting and meaningful research projects, and have published more than 20 academic papers on cryptography in high-profile and peer-reviewed international conferences and journals, like CRYPTO, EUROCRYPT, ASIACRYPT, SAC, TCHES (CHES), IACR Trans. Symmetric Cryptol.(FSE) and Journal of Cryptography. Moreover, I was the program committee of ASIACRYPT 2023, FSE 2024 and CRYPTO 2024, and served as the co-chair of FSE 2023.

Especially, I have been involved in the projects to analyze hash functions used in Bitcoin, candidates in NIST lightweight cryptography project and NIST post-quantum cryptography project, and novel symmetric-key primitives with real-world public-key applications, as briefly summarized below:

1) Cryptanalysis of the hash functions SHA-256 and RIPEMD-160 used in Bitcoin, and found the best collision attacks on them up till now.

2) Cryptanalysis of candidates in NIST lightweight cryptography project, and successfully broke the Round 2 candidate Gimli.

3) Cryptanalysis of candidates in NIST post-quantum cryptography project, breaking or revealing vulnerability in signature schemes like Picnic, AIMer, and Biscuit.

4) Developed novel algebraic cryptanalysis techniques and broke novel ciphers for public-key applications like LowMC, Agrasta, Chaghri, HERA, AIM.

My current research interest is as follows:

1) Hash functions

2) Post-quantum cryptography

3) algebraic cryptanalysis

• Yingxin Li, Fukang Liu, Gaoli Wang: New Records in Collision Attacks on SHA-2. To appear at EUROCRYPT 2024.
• Fukang Liu, Lorenzo Grassi, Clémence Bouvier, Willi Meier, Takanori Isobe: Coefficient Grouping for Complex Affine Layers. CRYPTO 2023. LNCS, vol 14083, pp 540-572. Springer, Cham (2023)
• Fukang Liu, Gaoli Wang, Santanu Sarkar, Ravi Anand, Willi Meier, Yingxin Li, Takanori Isobe: Analysis of RIPEMD-160: New Collision Attacks and Finding Characteristics with MILP. EUROCRYPT 2023. LNCS, vol 14007, pp 189-219. Springer, Cham (2023)
• Fukang Liu, Ravi Anand, Libo Wang, Willi Meier, Takanori Isobe: Coefficient Grouping: Breaking Chaghri and More. EUROCRYPT 2023. LNCS, vol 14007, pp 287-317. Springer, Cham (2023)
• Fukang Liu, Santanu Sarkar, Gaoli Wang, Willi Meier, Takanori Isobe: Algebraic Meet-in-the-Middle Attack on LowMC. ASIACRYPT 2022. LNCS, vol 13791, pp 225-255. Springer, Cham (2022)
• Fukang Liu, Santanu Sarkar, Willi Meier, Takanori Isobe: Algebraic Attacks on Rasta and Dasta Using Low-Degree Equations. In: Tibouchi M., Wang H. (eds) Advances in Cryptology – ASIACRYPT 2021. LNCS, vol 13090, pp 214-240. Springer, Cham (2021)
• Fukang Liu, Takanori Isobe , Willi Meier: Cryptanalysis of Full LowMC and LowMC-M with Algebraic Techniques. In: Malkin T., Peikert C. (eds) Advances in Cryptology – CRYPTO 2021. LNCS, vol 12827, pp 368-401. Springer, Cham (2021)
• Fukang Liu, Takanori Isobe , Willi Meier, Zhonghao Yang: Algebraic Attacks on Round-Reduced Keccak. In: Baek J., Ruj S. (eds) Information Security and Privacy. ACISP 2021. LNCS, vol 13083, pp 91-110. Springer, Cham (2021)
• Fukang Liu, Takanori Isobe , Willi Meier: Automatic Verification of Differential Characteristics: Application to Reduced Gimli. In: Micciancio D., Ristenpart T. (eds) Advances in Cryptology – CRYPTO 2020. CRYPTO 2020. LNCS, vol 12172, pp 219-248. Springer, Cham (2020)
• Subhadeep Banik and Zhenzhen Bao and Takanori Isobe and Hiroyasu Kubo and Fukang Liuand Kazuhiko Minematsu and Kosei Sakamoto and Nao Shibata and Maki Shigeri: WARP: Revisiting GFN for Lightweight 128-bit Block Cipher. In: Dunkelman O., Jacobson, Jr. M.J., O'Flynn C. (eds) Selected Areas in Cryptography – SAC 2020. SAC 2020. LNCS, vol 12804, pp 535-564. Springer, Cham (2020)
• Fukang Liu, Takanori Isobe: Iterative Differential Characteristic of TRIFLE-BC. In: Paterson K., Stebila D. (eds) Selected Areas in Cryptography – SAC 2019. SAC 2019. LNCS, vol 11959, pp 85-100. Springer, Cham (2019)
• Fukang Liu, Christoph Dobraunig, Florian Mendel, Takanori Isobe, Gaoli Wang, Zhenfu Cao: Efficient Collision Attack Frameworks for RIPEMD-160. In: Boldyreva A., Micciancio D. (eds) Advances in Cryptology – CRYPTO 2019. CRYPTO 2019. LNCS, vol 11693, pp 117-149. Springer, Cham (2019)
• Fukang Liu, Florian Mendel, Gaoli Wang: Collisions and Semi-Free-Start Collisions for Round-Reduced RIPEMD-160. In: Takagi T., Peyrin T. (eds) Advances in Cryptology – ASIACRYPT 2017. ASIACRYPT 2017. LNCS, vol 10624, pp 158-186. Springer, Cham (2017)

• Fukang Liu, Abul Kalam, Santanu Sarkar, Willi Meier: Algebraic Attack on FHE-Friendly Cipher HERA Using Multiple Collisions. IACR Transactions on Symmetric Cryptology, 2024(1), 214-233 (2024)
• Yingxin Li, Fukang Liu, Gaoli Wang: Automating Collision Attacks on RIPEMD-160. IACR Transactions on Symmetric Cryptology, 2023(4), 112-142 (2023)
• Fukang Liu, Mohammad Mahzoun, Morten Øygarden, Willi Meier: Algebraic Attacks on RAIN and AIM Using Equivalent Representations. IACR Transactions on Symmetric Cryptology, 2023(4), 166-186 (2023)
• Fukang Liu, Santanu Sarkar, Willi Meier, Takanori Isobe: New Low-Memory Algebraic Attacks on LowMC in the Picnic Setting. IACR Transactions on Symmetric Cryptology, 2022(3), 102-122 (2022)
• Fukang Liu, Willi Meier, Santanu Sarkar, Gaoli Wang, Ryoma Ito, Takanori Isobe: New Cryptanalysis of ZUC-256 Initialization using Modular Differences. IACR Transactions on Symmetric Cryptology, 2022(3), 152-190 (2022)
• Fukang Liu, Santanu Sarkar, Willi Meier, Takanori Isobe: The Inverse of $\chi$ and Its Applications to Rasta-like Ciphers. Journal of Cryptography 35, 28 (2022)
• Andrea Caforio, Subhadeep Banik, Yosuke Todo, Willi Meier, Takanori Isobe, Fukang Liu, Bin Zhang: Perfect Trees: Designing Energy-Optimal Symmetric Encryption Primitives. IACR Transactions on Symmetric Cryptology, 2021(4), 36–73 (2021)
• Fukang Liu, Takanori Isobe, Willi Meier, Kosei Sakamoto: Weak Keys in Reduced AEGIS and Tiaoxin, IACR Transactions on Symmetric Cryptology, 2021(2), 104-139 (2021)
• Kosei Sakamoto, Fukang Liu, Yuto Nakano, Shinsaku Kiyomoto, Takanori Isobe: Rocca: An Efficient AES-based Encryption Scheme for Beyond 5G, IACR Transactions on Symmetric Cryptology, 2021(2), 1-30 (2021)
• Fukang Liu, Takanori Isobe, Willi Meier: Exploiting Weak Diffusion of Gimli: Improved Distinguishers and Preimage Attacks. IACR Transactions on Symmetric Cryptology, 2021(1),185-216 (2021)
• Subhadeep Banik, Andrea Caforio, Takanori Isobe, Fukang Liu, Willi Meier, Kosei Sakamoto, Santanu Sarkar: Atom: A Stream Cipher with Double Key Filter. IACR Transactions on Symmetric Cryptology, 2021(1), 5-36 (2021)
• Subhadeep Banik, Takanori Isobe, Fukang Liu, Kazuhiko Minematsu, Kosei Sakamoto: Orthros: A Low-Latency PRF. IACR Transactions on Symmetric Cryptology, 2021(1), 37-77 (2021)
• Gaoli Wang, Fukang Liu, Binbin Cui, Florian Mendel, Christoph Dobraunig: Improved (semi-free-start/near-) collision and distinguishing attacks on round-reduced RIPEMD-160. Des. Codes Cryptogr. 88, 887–930 (2020).
• Fukang Liu, Takanori Isobe , Willi Meier: Cube-Based Cryptanalysis of Subterranean-SAE. IACR Transactions on Symmetric Cryptology, 2019(4), 192-222 (2019)
• Fukang Liu, Christoph Dobraunig, Florian Mendel, Takanori Isobe, Gaoli Wang, Zhenfu Cao: New Semi-Free-Start Collision Attack Framework for Reduced RIPEMD-160. IACR Transactions on Symmetric Cryptology, 2019(3), 169-192 (2019)
• Gaoli Wang, Yanzhao Shen, Fukang Liu: Cryptanalysis of 48-step RIPEMD-160. IACR Transactions on Symmetric Cryptology, 2017(2), 177-202 (2017)