The Cab of the Sleeping Horse. John Reed Scott
poise only that afternoon. He wanted to know what was inside that blank envelope. He was persuaded it contained that which would either solve the mystery of the cab, or would in itself lead on to a greater mystery. In either event, a most interesting document lay within his reach—and he took up the handkerchief. Discipline! The curb must be maintained.
And the handkerchief yielded nothing—not even when inspected under the drop-light and with the aid of a microscope. Not a mark to indicate who carried it nor whence it came.—Yet stay; in the closed room he detected what had been lost in the open: a faint, a very faint, odour as of azurea sachet. It was only a suggestion; vague and uncertain, and entirely absent at times. And Harleston shook his head. The very fact that there was nothing about it by which it might be identified indicated the deliberate purpose to avoid identification. He put it aside, and, taking up the roses, laid them under the light.
They were the usual American Beauties; only larger and more gorgeous than the general run—which might be taken as an indication of the wealth of the giver, or of the male desire to please the female; or of both. Of course, there was the possibility that the roses were of the woman's own buying; but women rarely waste their own money on American Beauties—and Harleston knew it. A minute examination convinced him that they had been crushed while being worn and then trampled on. The stems, some of the green leaves, and the edges of one of the blooms were scarred as by a heel; the rest of the blooms were crushed but not scarred. Which indicated violence—first gentle, then somewhat drastic.
He put the flowers aside and picked up the envelope, looked it over carefully, then, with a peculiarly thin and very sharp knife, he cut the sealing of the flap so neatly that it could be resealed and no one suspect it had been opened. As he turned back the flap, a small unmounted photograph fell out and lay face upward on the table.
Harleston gave a low whistle of surprise.
It was Madeline Spencer.
II—The Voice On The Wire
"Good morning, madame!" said Harleston, bowing to the photograph. "This is quite a surprise. You're taken very recently, and you're worth looking at for divers aesthetic reasons—none of which, however, is the 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 Vigenèrie 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