substitution ciphers using frequency analysis is based on the fact, that some letters, letter pairs and repeat letters are more frequent then others and some are rare, this pattern is translated to the cipher. Letters E, T, A and O are the most common in English text as well as pairs TH, ER, ON, and AN and doubles SS, EE , TT , and FF. If the text is long enough this information can be used to assign letters of alphabet to the letters of code, according to there fervency, repeating and length of words.…
Words 870 - Pages 4