Threefold General Key to Steganography (1608) - Page 12

GENERAL KEY TO STEGANOGRAPHY

...was the case, it will denote for you that many meaningful letters, and the immediately following number will signify that many [meaningless] ones Trithemius uses a binary-style system where certain numbers indicate how many letters in a sequence are part of the secret message ("meaningful") and how many are "nulls" or filler letters used to disguise it.:


The first mode is denoted thus	10 10 10 10 10 10 10 10 10, &c.
The second mode thus	01 01 01 01 01 01 01 01 01, &c.
The third thus	200 200 200 200 200 200 &c.
The fourth thus	002 002 002 002 002 002, &c.
The fifth mode thus	0001 0001 0001 0001 0001 0001, &c.
The sixth mode	1000 1000 1000 1000 1000 1000, &c.
The seventh mode thus	0002 0002 0002 0002 0002 0002, &c.
The eighth mode thus	2000 2000 2000 2000 2000 2000, &c.

Another general key is this, which is made in such a way, namely that the writer precedes and the Reader follows This describes a simple substitution cipher, specifically a Caesar shift where the writer uses the letter preceding the intended one in the alphabet (A becomes Z, B becomes A), and the reader decodes it by moving to the following letter., as in this example: Have mercy, almighty God, on the souls of your servants, etc. original: "Miserere omnipotens Deus animabus famulorum tuorum, &c." namely: lhrdqdqd nlmbrpsdmr edtr zmhlzatr ezltknqtl stnqtl, &c. And since these letters joined together in this way would mean nothing, they are held in our book similarly through the preceding eight examples or modes. The third and final general key is made in this way: if you wish to write, Have mercy, O God, etc. original: "Miserere Deus, &c." as above, you shall do so: namely, you will count all the letters of your message term: message (sensus); here referring to the plaintext or the "sense" of the secret communication., and however many there are, you will divide them into as many parts. For instance, if you wish to divide them into two parts, and you have 45 letters for one part of the sentence placed above, the divided parts will come to 22 for one part, and one remains, which you will always add to the end of the rest, and those in a similar way below...