GPT-6 Astra Deciphers WWI German Radio Message Encoded with ADFGVX Cipher

Cipher Background

Scienceblogs.de lists 50 unsolved ciphers, including German radio messages from World War I. These messages were encoded using the ADFGVX method, a transposition cipher that assigns two-letter coordinates to each character based on a keyword-generated polybius square. While many such messages have been decoded, over a dozen remained unsolved.

GPT-6 Astra's Solution

GPT-6 Astra successfully deciphered one of these previously unsolved messages, originally transmitted on November 27, 1918. The model identified "TRUPPENVERSCHIEBUNG" as the encryption word, a key documented in J. Rives Childs's "The History and Principles of German Military Ciphers, 1914–1918".

Decoded Message Content

The decoded German message reads: "EIN ENGLISCHER KREUZER EINLIEG X SEWASTOPOL X S4STEN X EIN GESCHWADER DER X ALLIIERTEN FOLGT 26STEN X". In English, this translates to: "AN ENGLISH CRUISER ARRIVED AT SEVASTOPOL ON THE ?4TH AN ALLIED SQUADRON FOLLOWS ON THE 26TH". The message details naval movements during the war.

Methodology

The ADFGVX method involves rearranging the encryption word alphabetically and then writing the encrypted message under it in rows. The specific column order, determined by the alphabetized encryption word, is crucial for decryption. GPT-6 Astra processed these steps to reconstruct the original message.