Cryptanalysis of the Enigma immense problem and it gave a great deal of trouble. Work on a high speed machine had been started by Wynn-Williams of the TRE late in 1941 and some nine months later Harold Keen of BTM started work independently. Early in 1942, Bletchley Park were a long way from possessing a high speed machine of any sort. Eventually, after a long period of being unable to decipher U-boat messages, a source of cribs was found. This was the Kurzsignale (short signals), a code which the German navy used to minimize the duration of transmissions, thereby reducing the risk of being
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