The Bot Left a Fingerprint: Detecting and Attributing LLM-Generated Passwords

In February 2026, researchers at Irregular published a detailed post about LLM-generated passwords, showing how passwords generated by LLMs follow notable patterns and are generally highly predictable. The root cause is fundamental: LLMs are optimized to predict probable outputs, which is the exact opposite of what secure password generation demands. That observation raised a natural follow-on question: if LLMs leave statistical fingerprints in the passwords they generate, can those fingerprin...