"obliterate" - 1 õppematerjal

TheCodeBreakers

7,000 miles, half of them in flat violation of the prerogatives of a nonbelligerent. But the cable from Stockholm to South America touched at England. Germany feared that British censorship might recognize the German codegroups in the Swedish messages and would stop the dispatches. So the German Foreign Office disguised the codegroups by enciphering them. This was done with Code 13040 in messages to Latin America and to Washington. Unfortunately for the Germans, the superencipherment did not obliterate all traces of the underlying code, which employed a distinctive mixture of 3-, 4-, and 5-digit codegroups. These traces aroused the suspicious of the ever-alert Room 40; it resolved the superencipherment, and Code 13040 reappeared. Room 40 then looked closely at other official Swedish messages. Many of them proved to be German as well; concealed under one superencipherment, for example, they found Code 0075. But this time England entered no protest. Hall