Exhibit | Aug. 4, 2021

Tunny and Sturgeon

The Tunny and Sturgeon machines (referred to as the "Fish" machines) were on-line cipher machines. Messages could be simultaneously enciphered and transmitted, saving a great deal of time. The Tunny (which is British slang for Tuna) was a German Army machine that could be used out of the back of a truck or at a fixed site. To create its encryption, the Tunny used the international telegraphic "Baudot" cipher and an additive placed on the cipher by the rotors. It was used to stream high-level teleprinter messages. The British built the first large valve programmable computer, Colossus, to decrypt Tunny messages, cutting decrypt time from weeks to hours. The Sturgeon was primarily a German Air Force system. It was capable of high-speed teleprinter transmissions. This particular machine used cable rather than radio to transmit its messages, thus decreasing the Allies' ability to intercept. A Swedish mathematician, Arne Beurling, was the first to break the Sturgeon, a feat he accomplished in just two weeks.