The Cab of the Sleeping Horse | Page 4

reason for your being in the envelope."
He drew out the sheet of paper and opened it. On it were typewritten, without address nor signature, these letters:
DPNFNZQFEFBPOYVOAEELEHHEJYD?BIWFTCCFVDXNQYCECLUGSUGDZYJ?ENRYUIGYBSNRTDUHJWHGYZIPEPA?WPPOIMCHEIPRFBJXFVWWFTZNJPY?UFJDILDCEMBRVZDAYVAWALUMOFN?FCVDPGLPWFUUWVIEPTKVIPUMSFZ?NPSJJRFYASGZSDACSIGYUOFCEXA?AOIDJJFCJPSONPKUUYVCVCTIHDP?XMNOYKENHUSKHYMSFRRPCYWSLLW?SMVPPUNEIFIDJLZRWEHPQGODFUZ?TCEMQIQWNFYJTAALUMHJXILEEHY?ISOVOAZUCUDINBRLUZICUOTTUSV?LPNFFVQFANPVCYJHILTPFISGHCW?HYICPPNFDOUOCLDUWEIVIPJNQBV?ZLMIJRVKDSFRLWEGBKQYWSFFBEI?YORHMYSHTECPUTMPJXFNRNEEUME?ILJBWV.
"Cipher!" commented Harleston, looking at it with half-closed eyes.... "The Blocked-Out Square, I imagine. No earthly use in trying to dig it out without the key-word; and the key-word--" he gave a shrug. "I'll let Carpenter try his hand on it; it's too much for me."
He knew from experience the futility of attempting the solution of a cipher by any but an expert; and even with an expert it was rarely successful.
As a general rule, the key to a secret cipher is discovered only by accident or by betrayal. There are hundreds of secret ciphers--any person can devise one--in everyday use by the various departments of the various governments; but, in the main, they are amplifications or variations of some half-dozen that have become generally accepted as susceptible of the quickest and simplest translation with the key, and the most puzzling without the key. Of these, the Blocked-Out Square, first used by Blaise de Vigen��rie in 1589, is probably still the most generally employed, and, because of its very simplicity, the most impossible of solution. Change the key-word and one has a new cipher. Any word will do; nor does it matter how often a letter is repeated; neither is one held to one word: it may be two or three or any reasonable number. Simply apply it to the alphabetic Blocked-Out Square and the message is evident; no books whatever are required. A slip of paper and a pencil are all that are necessary; any one can write the square; there is not any secret as to it. The secret is the key-word.
Harleston took a sheet of paper and wrote the square:
ABCDEFGHIJKLMNOPQRSTUVWXYZ?BCDEFGHIJKLMNOPQRSTUVWXYZA?CDEFGHIJKLMNOPQRSTUVWXYZAB?DEFGHIJKLMNOPQRSTUVWXYZABC?EFGHIJKLMNOPQRSTUVWXYZABCD?FGHIJKLMNOPQRSTUVWXYZABCDE?GHIJKLMNOPQRSTUVWXYZABCDEF?HIJKLMNOPQRSTUVWXYZABCDEFG?IJKLMNOPQRSTUVWXYZABCDEFGH?JKLMNOPQRSTUVWXYZABCDEFGHI?KLMNOPQRSTUVWXYZABCDEFGHIJ?LMNOPQRSTUVWXYZABCDEFGHIJK?MNOPQRSTUVWXYZABCDEFGHIJKL?NOPQRSTUVWXYZABCDEFGHIJKLM?OPQRSTUVWXYZABCDEFGHIJKLMN?PQRSTUVWXYZABCDEFGHIJKLMNO?QRSTUVWXYZABCDEFGHIJKLMNOP?RSTUVWXYZABCDEFGHIJKLMNOPQ?STUVWXYZABCDEFGHIJKLMNOPQR?TUVWXYZABCDEFGHIJKLMNOPQRS?UVWXYZABCDEFGHIJKLMNOPQRST?VWXYZABCDEFGHIJKLMNOPQRSTU?WXYZABCDEFGHIJKLMNOPQRSTUV?XYZABCDEFGHIJKLMNOPQRSTUVW?YZABCDEFGHIJKLMNOPQRSTUVWX?ZABCDEFGHIJKLMNOPQRSTUVWXY
Assume that the message to be transmitted is: "To-morrow sure," and that the key-word is: "In the inn." Write the key-word and under it the message:
INTHEINNINTH TOMORROWSURE
Then trace downward the I column of the top line of the square, and horizontally the T column at the side of the square until the two lines coincide in the letter B: the first letter of the cipher message. The N and the O yield B; the T and the M yield F; the H and the O yield V, and so on, until the completed message is:
BBFVVZBJAHKL
The translator of the cipher message simply reverses this proceeding. He knows the key-word, and he writes it above the cipher message:
INTHEINNINTH BBFVVZBJAHKL
He traces the I column until B is reached; the first letter in that line, T, is the first letter of the message--and so on.
Simple! Yes, childishly simple with the key-word; and the key-word can be carried in one's mind. Without the key-word, translation is impossible.
Harleston put down the paper and leaned back.
Altogether it was a most interesting collection, these four articles on the table. It was a pity that the cab and the sleeping horse were not among the exhibits. Number one: a lady's lace handkerchief Number two: three American Beauty roses, somewhat the worse for wear and violent usage. Number three: a cipher message. Number four: photograph of Madame--or Mademoiselle--de Cuthbert, de Spencer, de Lotzen. There was a pretty plot behind these exhibits; a pretty plot, or he missed his guess. It might concern the United States--and it might not. It would be his duty to find out. Meanwhile, the picture stirred memories that he had thought long dead. Also it suggested possibilities. It was some years since they had matched their wits against each other, and the last time she rather won out--because all the cards were hers, as well as the _mise en sc��ne_. And she had left--
His thought trailed off into silence; and the silence lasted so long, and he sat so still, that the ash fell unnoticed from his cigarette; and presently the cigarette burned itself into the tip, and to his fingers.
He tossed it into the tray and laughed quietly.
Rare days--those days of the vanished protocol and its finding! He could almost wish that they might be again; with a different _mise en sc��ne_, and a different ending--and a different client for his. He was becoming almost sentimental--and he was too old a bird for sentiment, and quite too old at this game; which had not any sentiment about it that was not pretence and sham. Yet it was a good game--a mighty entertaining game; where one measured wits with the best, and took long chances, and played for high stakes; men's lives and a nation's honour.
He picked up the photograph and regarded it thoughtfully.
"And what are to be the stakes now, I wonder," he mused. "It's another deal of the same old cards, but who are players? If America is one, then, my lady, we shall see who will