ChatGPT-6 Astra, OpenAI's latest model, has cracked an 85-year-old encrypted German military message. The so-called MVUEH transmission was sent by the German Army to the SS-Totenkopf Division on July 10, 1941. It was shared with enthusiasts online in 2005 but had remained undeciphered ever since. Researchers at Crypto Cellar now report that Astra decoded it in just two days.
How Astra Did It
What would have taken a human researcher weeks or months, Astra accomplished in two days. What makes the feat especially notable is how autonomous the process was. The model selected its target on its own after simply being asked whether it could break any of the unsolved Enigma messages on the Crypto Cellar website. Astra picked MVUEH Nr. 172 as a promising candidate, suspecting a connection to message Nr. 173 (SIPVX).
It chose the repeated place name "ROSENOW ROSENOW" as a probable plaintext crib, then independently wrote Python and C++ code to build an Enigma simulator and an Enigma Bombe. Using these tools, it broke the cipher. The decrypted 82-letter message reads roughly: "Please specify the route of march. I am in Rosenow. Immediate reply by radio." A spelling error at the start of the original transmission had complicated earlier decoding attempts.
What It Means
Crypto Cellar researchers are still reviewing the logs to understand exactly how Astra approached the problem. The result demonstrates what current AI models can achieve on complex analytical tasks. Enigma machines were long considered the benchmark for unbreakable encryption, and the efforts to defeat them in the 1940s contributed directly to the development of the first programmable digital computers. Just the week before, Astra had also cracked a 108-year-old WWI German code encrypted with the ADFGVX method.