USTC paper: matrix multiplication exponents below 9/4 would also speed up lattice sieving

jedisct1 · x · 2026-10-26

A new IACR ePrint preprint (2026/2622) by Yiming Gao and Honggang Hu of USTC, Faster Matrix Multiplication Leads to Faster Lattice Sieving, shows that under the spherical heuristic used in the BDGL analysis, if the matrix multiplication exponent ω ≤ 9/4−η for any fixed η>0, heuristic lattice sieving improves to (3/2−δ)^(n/2+o(n)) time.

Since OpenAI recently showed ω ≤ 9/4, any further speedup in matrix multiplication would directly cascade into lattice sieving — the core operation underlying lattice-based cryptography's security estimates. With known matrix multiplication algorithms, the method already yields subquadratic search within BDGL buckets. The authors ask whether the result generalizes to non-square (rectangular) matrix multiplication, which is faster than square. Shared via cryptographer jedisct1 relaying hashbreaker's commentary.

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