OpenAI GPT–6 Astra breaks Enigma message that has resisted solution since 2005

GPT-6 Astra independently broke the 1941 German Enigma message MVUEH (Nr. 172), revealing a key with wheel order 253 and a plaintext nearly identical to the previously solved SIPVX (Nr. 173). The break exploited a repeated place-name crib, ROSENOW, and corrected transcription errors, including a left-hand wheel turnover at the 72nd letter. The success followed a 2026 Bundesarchiv discovery of additional 1941 radio messages.