CIPHERS IN WAR

Timaru Herald, Volume CLI, Issue 22202, 20 February 1942, Page 6

CIPHERS IN WAR

BATHROOM SECRETS By E. E. P. Tisdall. (Editor of the war book and film “I Was a Spy” and author of “Spies Since the War” and “Unseen Hand. ’) The use of cioher is as old as the hills. Julius Caesar invented a system of sending messages to his friends which no one else would be able to read. And so in this most modern of wars there are people who want for one reason or another to send messages or information to the other side. Ciphering is simply the arrangement of letters of the alphabet in a certain manner which, when they reach their distination, can be given their correct value by means of a key common to both parties. If someone wished to send the message “Fleet leaves” he could use the simplest form of cipher by placing each letter in advance of the correct one. So that “Fleet leaves” would be written EKDDS KDZUDR. CU course, any newly-fledged member >f the deciphering service could read that, it is so simple. They could also read it even if the message was embodied in a letter, which might be written like this. 3/7/41. Dear Fred, Just a word or two to tell you how much I appreciated the photograph of your family. I hope to send you a new one o£ my little group shortly. The first thing would be to look at the date. This would probably be the guide and might mean that the message started' with the third letter and was embodied in every seventh letter until it came to a sign, such as a wrongly-spelled word, that the real message had ended. Ciphers differ from code in that cipher letters usually mean one letter equivalent; codes can mean a word or a sentence for each group of figures or letters. Fond of Darning During the last war there were some ingenious devices used for sending messages, ranging from the man who sang in his bath, to the old lady in Switzerland who was fond of darning shirts! The bathtub episode happened at Stockholm, where an agent suspected by the Allied secret service men, was being watched. All his telephone calls were tapped, his letters opened, and his friends interrogated, but to no purpose. Yet there were good grounds for believing that he was sending messages. All the Secret Service had to go on was the man’s irritating habit of singing in his bath, before an open window. But, since he sang no particular tune nor words that could at all be distinguished, they never learned anything. His “do. dum, dum, de da” meant nothing. And yet it was later proved to be a clever cipher, and a friend within earshot picked up the daily message, deciphered it, and sent it on its way by means of another cipher. The old lady who darned so well also was a clever agent. She lived on the border of Switzerland, and her customers included Germans. Laundry work was her main occupation, and from a certain German she received shirts which always seemed to have a tear in them. Like an efficient laundress she returned them neatly darned. But the authorities did not know that the thread was cleverly marked with little ink lines every so far along, it was an old trick, and all the German had to do was put the thread along a ruler 65 inches long (each quarter-inch representing a letter) and read out the letters, look up the meaning in the key, and the message was deciphered.