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Tales From The Black Chambers
THE MAKING AND BREAKING OF CODES AND CIPHERS HAS PLAYED AN EXCITING AND OFTEN CRUCIAL PART IN AMERICAN HISTORY
April 1973 | Volume 24, Issue 3
In December of 1863, in New York City, the postmaster intercepted a letter addressed to A. Keith in Halifax, Nova Scotia. Since that address was a known center of Confederate espionage, the letter was opened. It contained a message in a design cipher partially based on the Rosicrucian cipher. However, there were four other types of characters in the cipher. The message was turned over to three Army cryptographers.
Although the cipher appeared difficult to solve on the basis of only one message, there were vulnerable points, and the cryptographers seized upon these. Despite the fact that the message was in cipher, it had been written in the format of an ordinary letter. Quite obviously a date had been placed in the upper right-hand corner, a salutation was indicated, and a signature was affixed. In addition, two words, “reaches you,” had been written in the clear in the middle of the message. This was a critical weakness and the key to the attack, for it enabled the cryptographers to make a series of guesses as to the preceding words, then test them to see whether the resulting relationships of symbols to clear made sense elsewhere in the message. Their logical guess that the entire phrase might be “before this reaches you” struck pay dirt. With this as their lever they rapidly pried loose other symbols, and very soon the cipher fell apart.
The point of the message was that “12,000 rifled muskets came duly to hand and were shipped to Halifax as instructed.” The note ended with a plea for more money and was siened “I.H.C.”
With this information Union agents were able to confirm that a man named Cammack had purchased twelve thousand muskets and shipped them from New York to an unknown destination. However, the damage had already been done, as the muskets were beyond the Union’s grasp. To arrest Cammack at this point would serve no purpose, so the agents gave him rope.
Within a week he hanged himself. His next enciphered message, which of course was immediately deciphered, stated: “Say to Memminger [the Confederate Secretary of the Treasury] that Hilton will have the machines all finished and dies all cut ready for shipping by the first of January. The engraving of the plates is superb.” The message clearly implied that equipment for printing Confederate money was then in New York awaiting shipment to the Confederate government.
Hilton, the engraver, was quickly located and arrested, and the plates were seized along with several million dollars in printed Confederate money.
History sometimes smiles in her postscripts. The plates, as the message indicated, were indeed superb. Without good plates the Confederate Treasury had to resort to atrocious engravings. It became easy to tell counterfeit Confederate bills, which began turning up in the South, from the genuine currency because the real thing was a far cut below even the poorest bogus money in quality.
Only once has a head of state publicly announced, in effect, that he had a copy of a potential enemy’s diplomatic code book, and that man was an American President. The story started in the early days of World War I , when upon occupying Brussels the Germans found they had captured a powerful transmitter that was not in operating condition. They were told that a twenty-year-old student named Alexander Szek could repair it, and he was promptly given the job. When it was again on the air, the Germans used it to transmit espionage and diplomatic messages.
The furtive whisperings of the transmitter were, of course, picked up by British monitors, and some of the messages were partially broken. Their significance drew the attention of Admiral Sir Reginald Hall, the legendary director of naval intelligence, who turned his attention to the station. Intelligence agents, working through a Belgian agent, soon discovered that young Szek, who by now had become a trusted German code clerk, had been born in Croydon, just outside London, and quite possibly was anti-German. The Belgian agent approached Szek, gained his confidence, and, with the help of letters from Szek’s relatives in England, finally persuaded him to copy the diplomatic code book. Over a period of three months Szek copied the columns of figures, which were forwarded via the Belgian agent to London.
In January, 1917, German Foreign Minister Arthur Zimmermann sent an astonishing message to the German legation in Mexico. The message was transmitted through Count Johann von Bernstorff, the German ambassador in Washington, in 155 code groups of the “safe” diplomatic code. The German minister in Mexico was authorized, on behalf of the German government, to offer Mexico the three states of Texas, New Mexico, and Arizona if she would join Germany in a war against the United States. The British government, of course, decoded the message and disclosed its contents to President Wilson.