TheCodeBreakers
Britain was delaying her messages, Britain informed her that it had
positive knowledge of the unneutral practice. • The Swedish government
admitted this and promised that it would no longer send any German
messages to Washington. It did not. Instead, it sent them to Buenos
Aires. Here they were transferred from Swedish to German hands and
then forwarded to Washington. This was a circuitous route of about
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
annaabi.ee 
