SOLVING CIPHER SECRETS Edited by M. E. Ohaver "A CARRIER PIGEON FELL EXHAUSTED AT THEIR FEET." WHAT MESSAGE DOES IT BEAR. IN JULES VERNE'S IMMORTAL STORY? ILLE, n. A system of bars, posedly impossible, or at least materially especially of wrought iron, retarded. forming an open work bar• Thus the use of a grille, for instance, at rier, large or small, as a a window, or in preparing a cryptogram, is high fence inclosing a pub• for the purpose of preventing surreptitious lic building or across a pas• access to whatever lies beyond. And in this sageway, or the grating of a window. sense Webster's definition is as nicely suited {Webster.) to cryptography as to the intended meaning, This is the generally accepted meaning of since the grille is an open work barrier in the word grille. But to the cryptographer both cases. it takes on an added significance in that it Of grille ciphers there are many. The has been found convenient, because of a cer• invention of the original grille is attributed tain resemblance, to use the same term in to Jerome Cardan, the celebrated Italian designating the apparatus used in accom• physician and mathematician of the six• plishing certain types of ciphers. teenth century. And the simple grille de• The grille of cryptography, also com• scribed in this author's works will be treat• monly called a lattice or grating, is made ed in some detail in a later article. from any suitable flat material, as metallic An ingenious cipher derived from the plate, parchment, cardboard, or even paper, grille is said to have been used by the Ger• pierced with openings. mans during the World War. But probably The process of enciphering with a grille the most famous of the true grilles, and the varies with different types. But in every subject of this article, is that perfected in well known cipher of this kind the signifi• 1881 by Eduard B. Fleissner von Wostro- cant letters of the message are written witz, Austrian colonel, and author of a work through the openings or interstices of the on ciphers entitled, " Handhiic'i der Kryp- grille, the letters, letter groups, or words, tograpltie," published at Wien in the same thus being broken up from their original year. arrangement. Fictionists have had their fling at grille The key to a grille cipher is the disposi• ciphers. Honore de Balzac used a form of tion or arrangement of these openings, with• the original grille in 1881 in his " Histoire out knowledge of which any unauthorized des Trieze "—The Thirteen. Foe mentions reading of an enciphered message is sup• it. And to Jules Verne's story, " Mathais 634 FLYNN'S Sandorf," first published in 1885, the world To begin, then, this cipher is of the trans• is indebted for an example of Fleissner's position class, the letters retaining their grille. original values, being changed only in their Verne was the author of numerous tales of relative order. This transposition is ef• extravagant voyage and adventure. This fected by means of the grille, which, in its author's was the peculiar genius of inter• most usual form, operates upon a square weaving scientific fact with fiction, yet with of letters consisting of an even number a skill that lent his narratives all the plausi• of rows and columns. bility of truth. This even number may be 2, 4, 6, 8, 10, And Verne, too, was one of the first writ• or any other even number whatsoever. ers to realize the value of ciphers in fiction. Suppose for illustrative purposes a square Solving Cipher Secrets for June 6 has al• of 6 rows and columns, having a capacity ready dealt with his use of the Gronsfeld of (6x6=) 36 letters, be selected. cipher; and this exposition will similarly The preparation of the grille consists of include his use of the Fleissner grille in determining the locations of its openings, " Mathais Sandorf." the arrangement used being the key to the This story differs, however, from the ac• cipher. To do this it is first required to customed Verne yarn. It tells no tale of a divide the square into four equal smaller mechanical monster of the skies or of the squares, as indicated in the subjoined dia• deep. Nor yet of a delving into the bowels gram by the Roman numerals I, II, III, of the earth, or of an interplanetary flight and IV, and then to number the cells or through space. spaces of each of these four squares in an A more usual narrative, this, being merely exactly similar manner, also shown in the the relation of a series of adventures, strung drawing. on the thread of governmental intrigue. The story opens on the eighteenth day of May, 1867, which finds two penniless ad• I venturers wandering aimlessly about 1 Z I-* Trieste, the capital city of Illyria. 3 In due course they ascend the slopes of 4 the Karst hills, and find themselves eventu• ally in an inclosure, formerly a cemetery. 8 6N Here an exhausted carrier pigeon falls al• 7 9 most at their feet. Concealed under its NO ON 9 wing they discover a cipher message, of I which one of them, scenting conspiracy, CO makes an exact copy. 9 They now revive the bird, and, climbing sH into a high church tower overlooking the Z T city, they release it and, watching the course of its flight, are fortunately able to observe its destination. m One of the adventurers now obtains em• In a grille of this size there are nine ployment at this place, obtains the key by numbers in each of these four smaller stealth, and deciphers the cryptogram. squares. Upon which hinges the remainder of the In grilles constructed on squares of 8, 10, story. or 12, there would be 16, 25, or 36 numbers, The cipher, as it happens, is Fleissner's; respectively; and so on. and the key is one of the innumerable forms Now, for reasons that will soon be obvi• of the grille possible with this cipher. In ous, the number of apertures or windows order to make this more understandable in any grille of the type being described some knowledge of the structure and use of is always the same as the number of cells this cipher is necessary. in each of the four subdivisions of the larger SOLVING CIPHER SECRETS 635 square. In other words the number of French. Besides, Verne took the additional openings is equal to one-fourth of the num• but unavailing precaution, which we will ber of cells in the entire square. not, of writing his message backward before In the present instance, then, there must enciphering it. Here is Verne's message in be g openings. And having determined English: their number, it is now required to decide ALL IS READY. AT THE FIRST SIG• on their locations. NAL TH.Vr YOU SEND TO US FROM This may be done by selecting any de• TRIESTE. EVERY ONE WILL RISE TO- sired numbers in any of the squares, with r.F:THER FOR THE INDEPENDENCE OF the single restriction that each number he HUNGARY. used once, but once only. To encipher this message, place the grille Suppose that it is decided to use cells upon a piece of paper, with the marked edge 2, and g in square I: cells /, 5, and 7 in on the upper side.and at the top. It is con• square II; j, 4, and B, in square HI; and 6 venient to use paper ruled in squares of the in square IV; all of the numbers thus being same size as the subdivisions of the grille. used, but each one only once. This key, But this is not absolutely necessary, as the more conveniently expressed, could be space occupied by the grille may be out• written: lined on the paper with a pencil mark. 1: 2-Q. Now, taking the letters of the message II: 1-5-7. in their regular order, write the first letters HI: 5-4-8. IV: 6. through the openings of the grille, placing but one letter in each opening, and using If openings be now cut or punched in each opening once. In doing this the lines any desired flat material in accordance with of the grille must be taken in their order this key, indicating the front and top of the from top to bottom, and any openings in apparatus by some distinguishing mark, as the same line must be used in their order an A', or the word TOP, the completed grille from left to right. will appear as shown in the accompanying In the present case the first nine letters illustration. of the message, A-L-L-l-S-R-E-A-D, will, upon removal of the grille, be found written TOP on the paper in the following order: 0 0 0 0 A Z zT 0 / 0 0 S 0 /? £ 0 A Incidentally, you may be interested to D know that the grille just constructed is iden• tical with that used by \'erne in his story. Now give the grille one-quarter of a com• The grille prepared, next let us proceed plete turn in a clockwise direction, so that to the manner of using it. And to demon• the marked edge will be at the right. Then, strate this phase of the cipher since we have placing it upon the same space of the paper, used Verne's grille, nothing could be more write the second group of nine letters, fitting than also to use that author's mes• Y-A-T-T-H-E-F-I-R.