Chapter VI

On arbitrary Preparation accomplished by means of a Key;
also on Fortuitous Preparation accomplished by means of an Instrument.

The second Principal Mode depends on a key, and in this method the letters must be distributed in accordance with the norm of this key. This norm is the letter itself (see Bk.2.c.8), and, by its numerical position in the alphabet, it shows where the next letter is to be placed. For example, let us have the alphabet

If the secret be Fuge ocyus, write first the letter “F.” since “F” is the sixth letter in the alphabet, the following letter “U” must be put in the sixth place after this letter; and since “U” is the twentieth letter in the alphabet, the letter “G” must be put in the twentieth place after ‘U.” From which point you continue in this manner, you may produce from the secret a discourse like the following:

“Faustius tibi, mihi certe hihil gratius est tuo reditu, quom spe cityus accelerasti. Ni enim istud factum fuisset, ingens robus tuis damnum, ec.”

I should be remarked here that, if the number of the letter is doubled the opportunity for constructing discourse by this method is freer.

The third Mode depends on the familiar device of a thin, perforated plate: one or more letters of the secret are written by means of an opening , either wide or narrow, therein, and by the assistance of the same opening, the words are disclosed again to the reader. The method of constructing such an instrument and the Mode of writing therewith are clearly shown by Porta (Bk. 2.c.18), following Cardano and von Glauburg (in his Expositio ad Polygraph. Trithemii), and I will, therefore, add nothing further. See, above. Bk.2.c.9, and, below, Bk.6.cc.10&20, the instruments there described belonging quite properly here.