"efghiklmnopqrstuxyzwabcd" - 1 õppematerjal

TheCodeBreakers

Since there can be only as many rows as there are letters in the alphabet, the tableau is square. The simplest tableau is one that uses the normal alphabet in various positions as the cipher alphabets. Each cipher alphabet produces, in other words, a Caesar substitution.  This is precisely Trithemius' tableau, which he called his "tabula recta." Its first and last few lines were: abcdefghiklmnopqrstuxyzw bcdefghiklmnopqrstuxyzwa cdefghiklmnopqrstuxyzwab defghiklmnopqrstuxyzwabc efghiklmnopqrstuxyzwabcd ........................ zwabcdefghiklmnopqrstuxy wabodefghiklmnopqrstuxyz Trithemius used this tableau for his polyalphabetic encipherment, and in the simplest manner possible. He enciphered the first letter with the first alphabet, the second with the second, and so on. (He gave no separate plaintext alphabet, but the normal alphabet at the top can serve.) Thus a plaintext beginning Hunc caveto virum . . . became HXPF GFBMCZ FUEiB. ...