# AI cracks Enigma codes that stumped humans for decades

> OpenAI's Astra and Anthropic's Claude Opus 5 have solved two long-unsolved Nazi Enigma messages, achieving in days what would take human researchers weeks or months.
- Title: AI cracks Enigma codes that stumped humans for decades
- Summary: OpenAI's Astra and Anthropic's Claude Opus 5 have solved two long-unsolved Nazi Enigma messages, achieving in days what would take human researchers weeks or…
- Keywords: astra, openai, claude opus 5, anthropic, enigma, cryptanalysis, ai agents, carter leffen, jack willis, frode weierud, technology, startups
- Source: TechCrunch — https://techcrunch.com/2026/09/25/astra-and-opus-just-passed-turings-other-test
- Author: Tim Fernholz
- Published: 2026-09-25T17:24:36+00:00
- Read time: 1 min
- Topics: astra, openai, claude opus 5, anthropic, enigma, cryptanalysis, ai agents, carter leffen, jack willis, frode weierud, technology, startups
## Turing's other test
Alan Turing is famous for his intelligence test, but his real wartime achievement was cracking Nazi Germany's Enigma code during World War II using an early computer called the Bombe.
## Two messages finally decoded
Cryptanalysts say OpenAI's Astra and Anthropic's Claude Opus 5 have now cracked two long-unsolved Enigma messages that remained unbroken, usually due to mistranscription or encoder errors.
## Astra solves a 2005 mystery
Developer Carter Leffen asked OpenAI's Astra to search a database of Enigma messages and decode an unbroken one. The model found context clues, built an Enigma simulator, and recovered plaintext from a message that had baffled researchers since 2005.
## Validation and awe
Frode Weierud, a retired electrical engineer who maintains Crypto Cellar, a cryptology resource website, validated Leffen's solution. Weierud said the achievement left him in awe of what Astra accomplished.

> awe
## Professional cryptanalyst behaviour
Weierud noted that Astra behaved like a professional cryptanalyst and archive researcher. What the model achieved in two days would take a human researcher weeks or even months to accomplish.

> GPT, 6 Astra is behaving like a very professional cryptanalyst and archive researcher. What it has achieved in two days would take a human researcher weeks or even months.
## Claude Opus breaks another
On September 21, cybersecurity executive Jack Willis told Weierud he had used Anthropic's Claude Opus 5 to break a different unsolved message. Willis provided guidance and Claude used an officer's name signature to crack the code.
## Seven messages remain
Weierud notes that only seven unbroken Enigma messages remain, plus one where plaintext is known but the code is still unbroken. The AI breakthroughs suggest those may not stay unsolved for long.
## Key takeaway

Two AI models have decoded Enigma messages that cryptanalysts could not solve for years, demonstrating capabilities in archival research and pattern recognition that rival human expertise.