Book Two

Chapter VIII.

On Arbitrary Strewing of Letters, or
Strewing by the Use of a Key.

I have set forth that Strewing which protects itself by a kind of order of its own, reached by a fixed principle of arrangement. We come now to Arbitrary Strewing, the kind of Strewing, namely, that depends on an arbitrarily selected principle, and reaches through this its method of arrangement. This external principle Porta, Bk.II. c.15, calls a Key; the Mode in question is there presented by Porta rather obscurely. In order to come to a better understanding of the Mode, we must first make clear what is meant by a key. Key, as here understood metaphorically, is used in a general sense, in a special sense, and in an individual sense. In the general sense, when one understands a Mode of secret-making, he is said indefinitely to have the key. Thus, he who understands the principles of arrangement set forth in the preceding chapters, and, likewise, he who understands the laws, or incantations, contained in Bk. III., has found, we should say, the keys. In the special sense, the term key is used when we bring into use with accompanying rules, an external instrument wherein is contained the principle which locks and unlocks the secret. Since this process, again, is accomplished in two ways, either by means of some external sentence, letter or note, or by means of an instrument, different from these and constructed with skill, Porta, B.II. c.15, uses the word key in its individual sense, with reference to certain words taken at will from outside the sentence and brought into use. In this case the key is nothing else than such a sentence or such fixed words as those having the understanding of secret writing select or invent at their own will, to serve as a gauge whereby to make and unmake the arrangement; otherwise stated, it is such words as we employ to conceal the secret from others, but to deliver it for disclosure to the one who has understanding of the subject. In this strictly specialized sense, the word is used with a different signification from that wherein reference is made to a skillfully constructed external instrument, in which also lies the power of locking and unlocking, and which is treated in c.9, below. Furthermore, in this narrowest sense of the word, even alphabets, letters, points, virgules and numbers are called keys, inasmuch as they are employed as secondary locks on other devices. I shall call attention to these keys, in their proper places, as often as the need arises. This much being prefaced, let us now take up the Mode at hand, of which the method of procedure may be conveniently learned thus: Let us have as the secret text which it is desired to communicate to a single friend the sentence:  Spinola hatt Oppenheimb einbekonmen, dafur er Wormbs gerne gehabt. To begin with, let our first care be to count the letters of the given text; they are in this case 57.  When the number of letters has been found, we must mark on a sheet of paper the same number of points, equal distances apart. This done, we must, in the second place, take as a key wherewith to hide the secret the sentence:  Castum foderat Lucretia pectus:  or some other similar to it, the choice of sentence being a matter of individual preference. To this we will join the word Algazel, as being a barbarous word, and one, therefore, not likely to occur to the mind. The use of this key is to show the position which each letter will take by process of transference.  This process takes place and is accomplished thus:  We observe the number representing the place the key-letter holds in the alphabet, and then, counting the points in order, substitute, in the place