Lukasz Dworakowski

GPT-6 Astra has cracked *another* German WWI radio message encrypted with ADFGVX. This message, "RICHI-240", has a single known key, but, to my knowledge, was never cracked by humans before. My guess is that humans never solved this message because it has 20 characters *missing* for reasons unknown: the "240" in "RICHI-240" signifies that there should be 240 characters in the message, whereas in fact there are only 220. For purposes of cracking this cipher, the big problem is that it's not clear *where* these characters are missing from, because the order of the characters in the message is scrambled using the key. Thus, inserting the characters into the message in even slightly the wrong place leads to utterly nonsensical results. All this was no problem for GPT-6 Astra, which tried the key with various combinations of hypothetical places from which the characters could have been missing and scored the resulting blocks of text using patterns common in the German language. Relatively early on in the process, this approach rendered coherent German text! Inserting the 20 missing characters as a string between the 4th and 5th lines of text in the message worked! The message reads: AN O H L 11 ARMEE ALPENKORPS RAUM PETERREVE VERBASZ 21? 21? ? RDD LINIE NAGYBESSKEREK VERSECZ VERSECZ VON SERBEN BESETZT The three question marks you see are numerical digits, which cannot be restored by decryping (all we know is that they are three different digits from the following set: 5, 6, 7, 8, 9). And so, Astra was forced to check its results against historical WWI records. This search unearthed a French intelligence telegram, which described the situation in the area on November 11, 1918 and identified the German 217 - 219th infantry division and 6th Reserve Division in the area. Plugging in this missing information, we get the final result: AN O H L 11 ARMEE ALPENKORPS RAUM PETERREVE VERBASZ 217 219 6RDD LINIE NAGYBESSKEREK VERSECZ VERSECZ VON SERBEN BESETZT Or, in English: TO SUPREME ARMY COMMAND 11TH ARMY: ALPINE CORPS IN THE PETERREVE-VERBASZ AREA. 217TH - 219TH DIVISIONS, AND 6TH RESERVE DIVISION ON THE NAGYBECSKEREK-VERSEC LINE. VERSEC OCCUPIED BY SERBS. Astra checked the official history of the Serbian city of Vršac (Versec in Hungarian, and Werschetz in German) and found that, on November 10, 1918, German troops left the city and it was occupied by Serbian forces. RICHI-240 was sent at 3:38am on the following day to the German Supreme Army Command, informing them of this fact.