A B CJ K LS T U
D E FM N OV W X
G H IP Q RY Z

Fig. 1.—One of the earliest ciphers.

d j va o we p u
h l sb m ri y
g k tc q xf n z

Fig. 2.—Another arrangement of
cipher shown in [Fig. 1].

An example of another simple cipher created merely by the transposition of letters is shown in [Fig. 3], which can be read by taking the first letter of the first line, the last letter of the last line, the last letter of the first line, and the first letter of the last, then the last letter of the first line, the penultimate letter of the last, and so on. When the letters in [Fig. 3] are properly transposed they will be found to read “A very simple cipher.”

a y p e i e
c e p
h r i
r m l s v

Fig. 3.—Transposition of
letters cipher.

Lord Bacon invented a cipher composed of two letters only, which, although confusing to the uninitiated, is somewhat too cumbersome for any general use. Supposing the two letters decided upon to be A and B, they are grouped into series of five and employed in the following manner: The first letter in the alphabet, A, is represented by AAAAA, B becomes AAAAB, C appears as AAABA, D as AABAA. Using this combination, the same word “cipher” would be written AAABA, BBAAA, BBBBB, AABBA, ABAAA, BBBAB.

Amongst the easy ciphers must be mentioned that shown in [Fig. 4], which is used thus: In the center block of small type you find the letters of the word you wish to write in cipher. Suppose it to be TO-MORROW. Now in the vertical column at the side you find that the letter on a line with “t” is A, whilst the letter at the top of the vertical column is G. Therefore the cipher letters for “t” are AG. The next letter, “o,” is on a line with B and under E, so the cipher letters are BE. In a similar way “m” becomes CD, and, proceeding with the remaining letters in the same fashion, we obtain the whole word written in cipher thus: AG, BE, CD, BE, BF, BF, BE, CG.

ABCDEFGH
Aadgknqtx
Bbehloruvy
Ccfijmpswz