Analysis method of frequency analysis method

For example, e is the most commonly used letter in English, and its frequency of occurrence is one eighth. It is best to assume that the most commonly used symbol in long secret texts stands for E. If the cryptanalyst can decipher the nine most commonly used letters, such as E, T, A, O, N, I, R, S and H, he can decipher 70% of the passwords in general. The most modern encryption technology is also based on the ancient frequency analysis method.

Frequency analysis can also be used to analyze the position and combination of letters in words. For example, more than half of English words begin with t, a, o, s or w. Only 10 words (the, of, and, to, a, in, that, it, is and I) make up more than a quarter of the length of standard English articles.

The larger the coding vocabulary, the easier it is to decipher secrets through frequency analysis. In the fierce battle, the battlefield and headquarters sent messages back and forth one after another, among which secret messages were essential. During World War I, the Germans broadcast 2 million code words by radio every month. During World War II, the Allied High Command often broadcast 2 million words of coded text in one day.