Georges Painvin

Georges Jean Painvin (; 28 January 1886 – 21 January 1980) was a French geologist, professor, army captain, cryptanalyst, and industrialist, best known for breaking the German ADFGX and ADFGVX cipher systems during the First World War.

Early life Painvin was born into a family of École polytechnique graduates and mathematicians from Nantes. In addition to his distinguished scientific education, he was also a keen cellist, receiving First Prize for cello at the Nantes Conservatory of Music in 1902.

In 1905, Painvin passed his matriculation exam into the École polytechnique. In his second year, he opted for admission to the Corps des mines, where he would pursue his professional career. However, French military service briefly interrupted this path: on 7 September 1907, he was appointed reserve second lieutenant and assigned to the 33rd Artillery Regiment to complete his three years of obligatory service. In 1909 and again in 1911, he undertook only short periods of military duty lasting a few days. It was not until 1908 that Painvin entered the École Nationale Supérieure des Mines for a three-year study, where he ranked fourth out of six students in his class. Upon completion, he graduated as an engineer.

Painvin requested access to intercepted cryptograms transmitted by the invading Imperial German Forces. It was not long before he distinguished himself in the field of cryptanalysis. He was assigned to the Cabinet noir — the French black room — which he would occupy until the end of the war. The encrypted telegrams comprised both military and diplomatic communications, some transmitted as far afield as between Berlin and Constantinople. Within this role, Painvin focused on the cipher systems of the Imperial German Navy, followed by those of the Austro-Hungarian Navy, which had previously remained entirely indecipherable. He succeeded in breaking these codes, thereby enabling a more effective campaign against German submarines (U-boats). On 21 January 1915, Painvin proposed a method known as the ARC system, which allowed the cryptographic key to be identified from a single encrypted text. On 19 December 1973, Painvin was elevated to the rank of Grand Officer of the Legion of Honour.

The inventor of the ADFGX/ADFGVX cipher, the German signal corps officer Lieutenant , did not learn of Painvin's achievement until 1967. In 1966, nearly fifty years after the cipher's wartime use, Nebel discovered that his system had been broken during the First World War. He remarked that he had originally proposed a double-column transposition as the second stage of the encryption method. However, his suggestion was rejected by superiors in favour of a simpler — and cryptographically weaker — single-column transposition. Two years later, in 1968, Nebel and Painvin met in person. Nebel expressed his sentiments by saying that the enemies of yesterday meet as the friends of today. Painvin, in turn, noted that had Nebel's original proposal been adopted, he would not have succeeded in breaking the cipher. and noted that "in the minds of many people, Mr Painvin was regarded as pro-regime".

Under two demission proceedings — one before the Court of Justice of the Seine and the other before the Comité national interprofessionnel d'épuration (CNIE; National Interprofessional Purification Committee) — for acts of collaboration by French civilians during the German occupation of France, Painvin resigned as president and administrator of the Ugine steelworks on 12 December 1945. In the aftermath of the Second World War, he chose to withdraw from public life and relinquish most of his professional responsibilities.

In 1948, Painvin relocated to Casablanca, where in 1950 he was entrusted with the presidency of the industrial, financial, and services conglomerate Omnium Nord-Africain. He also served as delegate president of the Société Chérifienne d'Exploitation d'Ouvrages Maritimes and the Société Chérifienne du plâtre, and was a member of the Casablanca Chamber of Commerce and Industry.

Painvin retired in 1962 and returned to France at the age of 76. He died in 1980, aged 93.

Literature "The Codebreakers",

The Annals of Mines: Georges Jean PAINVIN (1886-1980) (in French).

References and notes