The TgS-1 DUDEK (Polish: hoopoe) (Dalekopisowe Urządzenie Do Elektronicznego Kodowania -- Teleprinter Device for Electronic Coding) was an on-line and off-line encryption system developed during the Cold War in the 1960s in the Polish People's Republic by the Telkom Teletra company and the Ministry of Interior for use on teleprinter circuits. The units saw use in the Polish Ministerstwo Spraw Wewnętrznych networks serving the (Milicja Obywatelska), the (Służba Bezpieczeństwa), the Polish Ministry of National Defense (Ministerstwo Obrony Narodowej), the Ministry of Foreign Affairs (Ministerstwo Spraw Zagranicznych) and the National Bank of Poland (Narodowy Bank Polski). The Poles also pressed Warsaw Pact states to adopt the DUDEK sets for international traffic.