Measuring LLMs’ Ability to Perform Cryptanalysis

304 · Bruce Schneier · July 29, 2026, 2:21 a.m.
Summary
This post discusses a new benchmark called CryptanalysisBench that evaluates large language models' (LLMs) ability to perform cryptanalysis on historical cryptographic algorithms. The results show that frontier models can discover known vulnerabilities and produce novel cryptanalytic attacks, demonstrating the growing capabilities of AI in the field of cybersecurity and mathematical reasoning.