German code breaking in World War II German code breaking in World War II German code breaking in World War II achieved some notable successes cracking British Naval ciphers until well into the fourth year of the war, but also suffered from a problem typical of the German armed forces of the time: numerous branches and institutions maintained their own cryptographic departments, working on their own without collaboration or sharing results with equivalent units. This led to duplicated effort, to a fragmentation of potential, and to lower efficiency than might have been achieved. There was no central German cryptography agency comparable to the British Bletchley Park facility.
Polish contribution to World War II the only World War II resistance movement to manufacture large quantities of weaponry and munitions. In addition to production of pre-war designs they developed and produced during the war the Błyskawica submachine gun, Bechowiec, KIS and Polski Sten machine pistols as well as the filipinka and sidolówka hand grenades. During the Warsaw Uprising Polish engineers built several armoured cars, such as the Kubuś, which also took part in the fighting. The KIS was designed and made in the Jan Piwnik's "Ponury" ("Grim") guerrilla unit that was operating in Holy Cross Mountains region. It was probably the only kind of modern