The black cipher represented a sophisticated encryption tool utilized by the Sith Empire following its creation by Imperial Intelligence. The Galactic Republic knew it as the "Umbra encrypter," and it was regarded as the most cutting-edge encryption technology ever conceived, enabling flawless and untraceable communication and encoding.
As of 3640 BBY, a mere seventeen operational ciphers were in existence: fifteen were installed on the Empire's largest capital ships, while the other two were located in the Minister of Logistics' office, situated within the Orbital Defense Command Center, and held by Darth Marr. In the initial phases of the Galactic War, Sergeant Yuun collaborated with Havoc Squad to reconstruct a black cipher from debris on Hoth, and the Republic Strategic Information Service repeatedly attempted to extract ciphers from Imperial vessels, only to be thwarted by their self-destruct mechanisms. Furthermore, should the Empire suspect a black cipher's security had been breached, they would order all their capital ships back to port for code alterations. The successful acquisition of the Minister of Logistics' cipher was a pivotal component of Operation End Game.