The changes in Ottoman diplomatic cryptography and its methods during the 19th century (1811–1877)

Abstract In parallel with the change in the understanding of diplomacy during the reign of Selim III, the Ottoman Empire started to use diplomatic cryptography. However, the efforts which started in 1797 were interrupted to a great extent when the ambassadors were recalled to the state after 1811. In the following period, Chargé d’affaires took over their duties and continued to use cryptography. With the reassignment of ambassadors to European capitals after 1834, Ottoman diplomatic cryptography stepped into a new era. In this study, the process until 1877 is discussed in the light of encrypted documents found in Ottoman archives. Codes and coding/decoding methods of Ottoman diplomats throughout the period are also examined.