# OpenAI’s Astra and Anthropic’s Opus break two unsolved Enigma messages

Digest AI · Research · published 2026-09-25T17:24:36Z

Canonical: https://digestai.news/story/openais-astra-and-anthropics-opus-break-two-unsolved-enigma-messages

## Summary

Two cryptanalysts used OpenAI’s GPT-6 Astra and Anthropic’s Claude Opus 5 to decode two long-unsolved Enigma-encoded messages from World War II. Carter Leffen prompted Astra to find and break a message that had stumped researchers since 2005. The model located archival clues, simulated the Enigma machine, and recovered the plaintext in days—work that would take humans weeks or months, according to Frode Weirerud, who maintains the Crypto Cellar database and validated the result. Weirerud noted Astra’s logs referenced private collections not hosted on his site, leaving open whether the model accessed them or inferred the data from public sources.

Jack Willis used Opus 5 to break a second unsolved message by leveraging a known officer’s signature. Weirerud confirmed only seven Enigma messages remain unbroken, plus one with known plaintext but unresolved code. The demonstrations highlight how advanced LLMs can replicate complex historical research tasks with speed and precision.

## Key points

- OpenAI’s GPT-6 Astra decoded a 2005-unsolved Enigma message in days, using archival research and simulation
- Anthropic’s Claude Opus 5 broke another message by identifying an officer’s known signature pattern
- Only seven Enigma messages remain unbroken, per Crypto Cellar’s Frode Weirerud

## Why it matters

The breakthroughs show LLMs can perform specialized historical research—like cryptanalysis—with efficiency rivaling human experts, raising questions about their potential for uncovering lost data or verifying archival claims.

## Sources

1. [Astra and Opus just passed Turing’s other test](https://techcrunch.com/2026/09/25/astra-and-opus-just-passed-turings-other-test) (TechCrunch AI, 2026-09-25)

Part of the developing story: [AI Deciphers Nazi Enigma Secrets](https://digestai.news/thread/openai-s-gpt-6-astra-decrypts-83yearold-nazi-enigma-message-in-ten-hours) (2 stories)

## Cite

Digest AI, "OpenAI’s Astra and Anthropic’s Opus break two unsolved Enigma messages", 25 September 2026, https://digestai.news/story/openais-astra-and-anthropics-opus-break-two-unsolved-enigma-messages

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