Refugees of the Greek Civil War these children were "Greek" but no distinction was made regarding the ethnicity of the children. There were also ethnically Macedonian and Albanian children who had also been sent to the country. Unlike the rest of Eastern Europe the Macedonian language was not taught to the children in Germany, since the majority were Greek Macedonians. Mostly, the Greek children would end up returning to Greece. A large proportion of the adults who had left Europe ended up in the United States, Canada and Australia. Thousands would go on to establish themselves in the hope of returning to Europe. The 1950s witnessed
S-box years out of a concern that a "backdoor" — a vulnerability known only to its designers — might have been planted in the cipher. The S-box design criteria were eventually published (in ) after the public rediscovery of differential cryptanalysis, showing that they had been carefully tuned to increase resistance against this specific attack. Biham and Shamir found that even small modifications to an S-box could significantly weaken DES. There has been a great deal of research into the design of good S-boxes, and much more is understood about their use in block ciphers than when DES was released. Any