Sabine Baring-Gould - Curiosities of Olden Times стр 5.

A curious instance of this occurred at the close of the sixteenth century, when the Spaniards were endeavouring to establish relations between the scattered branches of their vast monarchy, which at that period embraced a large portion of Italy, the Low Countries, the Philippines, and enormous districts in the New World. They accordingly invented a cypher, which they varied from time to time, in order to disconcert those who might attempt to pry into the mysteries of their correspondence. The cypher, composed of fifty signs, was of great value to them through all the troubles of the Ligue, and the wars then desolating Europe. Some of their despatches having been intercepted, Henry IV. handed them over to a clever mathematician, Viete, with the request that he would find the clue. He did so, and was able also to follow it as it varied, and France profited for two years by his discovery. The court of Spain, disconcerted at this, accused Viete before the Roman court as a sorcerer and in league with the devil. This proceeding only gave rise to laughter and ridicule.

A still more remarkable instance is that of a German professor, Hermann, who boasted, in 1752, that he had discovered a cryptograph absolutely incapable of being deciphered, without the clue being given by him; and he defied all the savants and learned societies of Europe to discover the key. However, a French refugee, named Beguelin, managed after eight days study to read it. This cypher though we have the rules upon which it is formed before us is to us perfectly unintelligible. It is grounded on some changes of numbers and symbols; numbers vary, being at one time multiplied, at another added, and become so complicated that the letter e, which occurs nine times in the paragraph, is represented in eight different ways; n is used eight times, and has seven various signs. Indeed the same letter is scarcely ever represented by the same figure; but this is not all: the character which appears in the place of i takes that of n shortly after; another symbol for n stands also for t. How any man could have solved the mystery of this cypher is astonishing.

Now let me recommend a far simpler system, and one which is very difficult of detection. It consists of a combination of numbers and letters. Both parties must be agreed on an arrangement such as that in the second line below, for on it all depends.

Now in turning a sentence such as The army must retire into cypher, you count the letters which make the sentence, and find that T is the first, H the second, E the third, A the fourth, R the fifth, and so on. Then look at the table. T is the first letter; 4 answers to 1; therefore write the fourth letter in the place of T; that is A instead of T. For h the second, put the seventh, which is y; for E, take the second, h. The sentence will stand Ayh utsr emma yhutsr. It is all but impossible to discover this cypher.

All these cryptographs consist in the exchange of numbers or characters for the real letters; but there are other methods quite as intricate, which dispense with them.

The mysterious cards of the Count de Vergennes are an instance. De Vergennes was Minister of Foreign Affairs under Louis XVI., and he made use of cards of a peculiar nature in his relations with the diplomatic agents of France. These cards were used in letters of recommendation or passports which were given to strangers about to enter France; they were intended to furnish information without the knowledge of the bearers. This was the system. The card given to a man contained only a few words, such as:

The card told more tales than the words written on it. Its colour indicated the nation of the stranger. Yellow showed him to be English; red, Spanish; white, Portuguese; green, Dutch; red and white, Italian; red and green, Swiss; green and white, Russian; etc. The persons age was expressed by the shape of the card. If it were circular, he was under 25; oval, between 25 and 30; octagonal, between 30 and 45; hexagonal, between 45 and 50; square, between 50 and 60; and oblong showed that he was over 60. Two lines placed below the name of the bearer indicated his build. If he were tall and lean, the lines were waving and parallel; tall and stout, they converged; and so on. The expression of his face was shown by a flower in the border. A rose designated an open and amiable countenance, whilst a tulip marked a pensive and aristocratic appearance. A fillet round the border, according to its length, told whether the man was bachelor, married, or widower. Dots gave information as to his position and fortune. A full stop after his name showed that he was a Catholic; a semicolon, that he was a Lutheran; a comma, that he was a Calvinist; a dash, that he was a Jew; no stop indicated him as an Atheist. So also his morals and character were pointed out by a pattern in the angles of the card, such as one of these:

Consequently, at one glance the minister could tell all about his man, whether he were a gamester or a duellist; what was his purpose in visiting France; whether in search of a wife or to claim a legacy; what was his profession that of physician, lawyer, or man of letters; whether he were to be put under surveillance or allowed to go his way unmolested.

We come now to a class of cypher which requires a certain amount of literary dexterity to conceal the clue.

During the Great Rebellion, Sir John Trevanion, a distinguished Cavalier, was made prisoner, and locked up in Colchester Castle. Sir Charles Lucas and Sir George Lisle had just been made examples of, as a warning to malignants: and Trevanion has every reason for expecting a similar bloody end. As he awaits his doom, indulging in a hearty curse in round Cavalier terms at the canting, crop-eared scoundrels who hold him in durance vile, and muttering a wish that he had fallen, sword in hand, facing the foe, he is startled by the entrance of the gaoler who hands him a letter:

Mayt do thee good, growls the fellow; it has been well looked to before it was permitted to come to thee.

Sir John takes the letter, and the gaoler leaves him his lamp by which to read it:

Worthie Sir John Hope, that is ye beste comfort of ye afflictyd, cannot much, I fear me, help you now. That I wolde saye to you, is this only: if ever I may be able to requite that I do owe you, stand not upon asking of me. Tis not much I can do: but what I can do, bee you verie sure I wille. I knowe that, if dethe comes, if ordinary men fear it, it frights not you, accounting it for a high honour, to have such a rewarde of your loyalty. Pray yet that you may be spared this soe bitter, cup. I fear not that you will grudge any sufferings: only if bie submission you can turn them away, tis the part of a wise man. Tell me, an if you can, to do for you any thinge that you wolde have done. The general goes back on Wednesday. Restinge your servant to command.

R. T.

Now this letter was written according to a preconcerted cypher. Every third letter after a stop was to tell. In this way Sir John made out Panel at east end of chapel slides. On the following even, the prisoner begged to be allowed to pass an hour of private devotion in the chapel. By means of a bribe, this was accomplished. Before the hour had expired, the chapel was empty the bird had flown.