The black cipher was an encryption device that was used by the Sith Empire after its development by Imperial Intelligence. Known to the Galactic Republic as the "Umbra encrypter", the cipher was considered to be the most advanced encryption machine ever designed. In 3640 BBY, only seventeen intact ciphers existed, with fifteen installed aboard the Empire's largest capital ships and the remaining two in the Minister of Logistics' office in the Orbital Defense Command Center and in the possession of Darth Marr. During the early stages of the Galactic War, Sergeant Yuun worked with Havoc Squad to reassemble a black cipher from wreckage on Hoth, and the Republic Strategic Information Service tried many times to retrieve ciphers from Imperial ships but were foiled by their self-destruct mechani