● Covered by 1 source · 1 reportMedium impact1 neutral
OpenAI GPT-6 Astra Breaks 1941 Enigma Message Unsolved Since 2005
Key points
- GPT-6 Astra broke the 1941 Enigma message MVUEH.
- The message had resisted decryption attempts since 2005.
- The AI independently selected the message and found its key.
- The plaintext was similar to another message, SIPVX.
AI Deciphers Long-Unbroken Enigma Code
On September 15, 2026, Carter Leffer confirmed that OpenAI's GPT-6 Astra had successfully broken the German Army Enigma message MVUEH, sent on July 10, 1941. This particular message, logged as Nr. 172, had remained undeciphered despite continuous efforts since 2005.
Independent AI Initiative
Carter Leffer tasked GPT-6 Astra with attempting to break any of the unbroken Enigma messages listed on the Crypto Cellar Research webpage. The AI autonomously identified MVUEH as the most promising target and suspected a connection between its plaintext and that of message Nr. 173, SIPVX, which had been broken in 2017.
Key and Plaintext Discovery
The key for MVUEH was found to be entirely different from other keys used on July 10, 1941, including a different wheel order (253 instead of 512). The plaintext of MVUEH was nearly identical to that of SIPVX, differing only by twelve letters due to a transcription error in MVUEH and a repeated signature in SIPVX.
Challenges in Previous Decryption Attempts
Analysis of the successful break revealed that previous attempts were likely hindered by several factors. The original transcription of the MVUEH ciphertext contained multiple errors. Additionally, the Enigma's left-hand wheel performed a turnover at the 72nd letter, a rare occurrence known to complicate decryption efforts.
✨ This summary was generated by AI from the outlets' reporting listed below. It is not independently verified and may contain errors — check the original sources. How BrevFeed works →
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Reporting from
OpenAI's GPT-6 Astra successfully deciphered the German Army Enigma message MVUEH from July 10, 1941, which had remained unbroken since 2005. The AI independently identified the message as a promising target and discovered its key, which differed significantly from other messages from the same day, and found its plaintext was nearly identical to another previously broken message.