Lewis Carroll created a lovely, simple cipher in the midst of his Alice andSnark and Logic and Sylvie publications. It really is just a simple bit of polyalphabetic substitution, bu tit gets the job done. (Many others have walked this royal road: Leon Battista Alberti, A Treatise on Ciphers, [De componendis cyfris]; Giovan Battista Belaso, La cifra del Sig. Giovan Battista Bel[l]aso, gentil’huomo bresciano, nuovamente da lui medesimo ridotta à grandissima brevità et perfettione, Venetia 1553 (and also hisNovi et singolari modi di cifrare de l’eccellente dottore di legge Messer Giouan Battista Bellaso nobile bresciano, Lodovico Britannico, Brescia 1555); Giombatista Della Porta, De furtivis literarum notis vulgo de ziferis, G. M. Scoto, Neapoli 1563; Galileo Galilei, Intorno a due nuove scienze,Opere, . Vol. VIII, Firenze; Blaise de Vgenere, Traicté des chiffres ou secrètes manières d’escrire, Abel l’Angelier, Paris, 1586; and so on...its a very wide literature, even pre-18th century). Louis Carroll. Louis "Cipher" Carroll. Comes sort of goofily close to "Louis Cipher". Lucifer. Not the case, of course unless you were trying to figure out one of his tricky puzzles.
Perhaps it is the cipher's presentation and design and simplicity, its elegance, that I like so much. It reminds me in some ways of the Henry Holidaymasterpiece of nothignness created for Carroll's Hunting of the Snark--and that of course would be the Bellman's map, a map of nothing, a map showing nothing at all to the sailors who must follow it and who were all happy that the map had nothing to obstruct their vision of possibility and blank expectation. (I wrote about that in The Most Beautiful Map in the World, here). It is interesting to note that none of the illustrators who followed Holiday chose to illustrate the nothing map with such nothingness as in Carroll--there would be hands on it, or the map would be oblique, or not the central image of the illustration. Holiday's map was just that--straightforward, simple, strong).
I've decided to make this a part of the History of Blank, Empty and Missing Things series simply because everything is missing unless you have the missing key--here you have all the parts of the puzzle, and then some, everything that you need to solve it, save for the integral part of ordering.
From Carrolls's text:
Explanation
Each column of this table forms a dictionary of symbols representing the alphabet: thus, in the A column, the symbol is the same as the letter represented; in the B column, A is represented by B, B by C, and so on.
To use the table, some word or sentence should be agreed on by two correspondents. This may be called the 'key-word', or 'key-sentence', and should be carried in the memory only.
In sending a message, write the key-word over it, letter for letter, repeating it as often as may be necessary: the letters of the key-word will indicate which column is to be used in translating each letter of the message, the symbols for which should be written underneath: then copy out the symbols only, and destroy the first paper. It will now be impossible for any one, ignorant of the key-word, to decipher the message, even with the help of the table.
For example, let the key-word be vigilance, and the message 'meet me on Tuesday evening at seven', the first paper will read as follows—
v i g i l a n c e v i g i l a n c e v i g i l a n c e v im e e t m e o n t u e s d a y e v e n i n g a t s e v e nh m k b x e b p x p m y l l y r x i i q t o l t f g z z v
The second will contain only 'h m k b x e b p x p m y l l y r x i i q t o l t f g z z v'.
The receiver of the message can, by the same process, retranslate it into English.
If this table is lost, it can easily be written out from memory, by observing that the first symbol in each column is the same as the letter naming the column, and that they are continued downwards in alphabetical order. It would only be necessary to write out the particular columns required by the key-word, but such a paper would afford an adversary the means for discovering the key-word.
