ⓗⓔⓛⓛⓞ! ϞϞ(๑⚈ ․̫ ⚈๑)∩

🔴 I am currently looking for a postdoc.

Now I am a PhD student under the guidance of Yanbin Pan and I also spent one year in the Crypto Group at Aarhus University, hosted by Diego F. Aranha. My research interests primarily focus on applying Algorithmic Number Theory and Combinatorics to problems in Cryptography. I prefer problems with a strong mathematical structure, such as those with an algebraic or combinatorial flavor.

Together with my collaborators, we introduced additive combinatorics into Coppersmith’s method, which enabled us to remove manual calculations of success conditions. This work was accepted to Crypto’25, and we also have several interesting applications and follow-up results.

Currently, I am interested in leakage-resilient secret sharing, not only in terms of lower bounds but also in proving security. I particularly enjoy the Fourier analysis and additive combinatorics tools used in this area.

Selected Publications

ヾ(＾∇＾) Some of my favourite results (A full list of publications):

• Computing Asymptotic Bounds for Small Roots in Coppersmith’s Method via Sumset Theory.
  Yansong Feng, Hengyi Luo, Qiyuan Chen, Abderrahmane Nitaj, Yanbin Pan.
  Crypto 2025 [PDF][CODE]
  By introducing the Sumsets theory from Additive Combinatorics as a new analytical tool, we develop the first provable algorithm for determining these asymptotic bounds, which significantly streamlines manual calculations.

• On Factoring and Power Divisor Problems via Rank-3 Lattices and the Second Vector.
  Yiming Gao, Yansong Feng, Honggang Hu, Yanbin Pan.
  [PDF]
  Based on the baby-step giant-step technique, we propose several algorithms for integer factorization. An interesting observation is that the shortest vector typically yields a trivial collision, but the second shortest vector gives a non-trivial collision.

• Small Public Exponent Brings More: Improved Partial Key Exposure Attacks against RSA.
  Yansong Feng, Abderrahmane Nitaj, Yanbin Pan.
  CIC 2024 [PDF][CODE]
  We improve the attack by Boneh et al. at Asiacrypt ‘98 and achieve a 2^10 (or 1,024) x improvement in the running time for e = 65,537.

• Embedding Integer Lattices as Ideals into Polynomial Rings.
  Yihang Cheng, Yansong Feng, Yanbin Pan.
  ISSAC 2024 [PDF][CODE]
  An algorithm to verify whether a given full-rank lattice in Z^n is an ideal lattice and output all the polynomial rings.

• Generalized Implicit Factorization Problem.
  Yansong Feng, Abderrahmane Nitaj, Yanbin Pan.
  SAC 2023 [PDF][CODE]

Activities

Trips & Talks

External Reviewer: IEEE TDSC 2025, Africacrypt 2025, Asiacrypt 2025

Miscellaneous

Ƶƶ(☄￣▵—▵￣)

• [Useful-Link] A cute website contains many useful links.

Contact

Github | DBLP | Google Scholar | fengyansong [at] amss.ac.cn