HKB
human ingenuity may not, by proper application, resolve. In fact, having once established connected and legible characters, I scarcely gave a thought to the mere difficulty of developing their import.
"In the present case--indeed in all cases of secret writing--the question regards the language of the cipher; for the principles of solution, so far especially as the more simple ciphers are concerned, depend upon, and are varied by, the genius of the particular idiom. In general, there is no alternative but experiment (directed by probabilities) of every tongue known to him who attempts the solution, until the true one be attained. But, with the cipher now before us, all difficulty was removed by the signature. The pun upon the word 'Kidd' is appreciable in no other language than the English. But for this consideration I should have begun my attempts with the Spanish and French, as the tongues in which a secret of this kind would most naturally have been written by a pirate of the Spanish main. As it was, I assumed the cryptograph to be English.
"You observe there are no divisions between the words. Had there been divisions, the task would have been comparatively easy. In such cases I should have commenced with a collation and analysis of the shorter words, and, had a word of a single letter occurred, as it is most likely (a or I, for example), I should have considered the solution as assured. But, there being no division, my first step was to ascertain the predominant letters, as well as the least frequent. Counting all, I constructed a table thus:--
Of the character 8 there are 33 ; " 26 4 " 19 #) " 16 * " 13 5 " 12 6 " 11 ( " 10 +1 " 8 0 " 6 92 " 5 :3 " 4 ? " 3 ¶ " 2 ]--. " 1
"Now, in English, the letter which most frequently occurs is e. Afterward, the succession runs thus: a o i d h n r s t u y c f g l m w b k p q x z*. *E predominates so remarkably that an individual sentence of any length is rarely seen in which it is not the prevailing character.
"Here, then, we have, in the very beginning, the groundwork for something more than a mere guess. The general use which may be made of the table is obvious, but, in this particular cipher, we shall only very partially require its aid. As our predominant character is 8, we will commence by assuming it as the e of the natural alphabet. To verify the supposition, let us observe if the 8 be seen often in couples--for e is doubled with great frequency in English--in such words, for example, as 'meet,' 'fleet,' 'speed,' 'seen,' 'been,' 'agree,' etc. In the present instance we see it doubled no less than five times, although the cryptograph is brief.
"Let us assume 8, then, as e. Now, of all the words in the language, 'the' is most usual; let us see, therefore, whether there are not repetitions of any three characters, in the same order of collocation, the last of them being 8. If we discover repetitions of such letters, so arranged, they will most probably represent the word 'the.' Upon inspection, we find no less than seven such arrangements, the characters being;48. We may, therefore, assume that; represents t, 4 represents h, and 8 represents e--the last being now well confirmed. Thus a great step has been taken.