MilestoneTheory & algorithmsRefuted
Chen proposes a quantum lattice algorithm, then identifies a fatal bug
Apr 10, 2024
Yilei Chen claims a polynomial-time quantum algorithm for a range of Learning With Errors problems. On April 18 he acknowledges an uncorrected bug and says the claim no longer holds; the paper does not establish a break of lattice-based cryptography.
Why it matters
The episode tests a proposed quantum attack on a problem underlying post-quantum cryptography and shows why an unchecked preprint cannot establish a cryptographic break.
Chen's April 18 update identifies a bug in step 9 and explicitly says the claimed algorithm does not hold. This refutes that construction, not the possibility of future quantum algorithms for Learning With Errors.
Yilei Chen
Added Oct 27, 2026. Spotted an error? Tell us and we will review it.