The Codebreakers: The Comprehensive History of Secret Communication from Ancient Times to the Internet

To plug up as many steganographic channels of communication as possible, the Office of Censorship banned in advance the sending of whole classes of objects or kinds of messages. International chess games by mail were stopped. Crossword puzzles were extracted from letters, for the examiners did not have time to solve them to see if they concealed a secret message, and so were newspaper clippings, which might have spelled out messages by dotting successive letters with secret ink-a modern version of a system described more than 2,000 years earlier by Aeneas the Tactician. Listing of students’ grades was tabooed. One letter containing knitting instructions was held up long enough for an examiner to knit a sweater to see if the given sequence of knit two and cast off contained a hidden message like that of Madame Defarge, who knitted into her “shrouds” the names of further enemies of the French Republic, “whose lives the guillotine then surely swallowed up.” Childish scrawls, sent from proud parents to proud grandparents, were removed because of the possibility of their covering a map. Even lovers’ X’s, meant as kisses, were heartlessly deleted if censors thought they might be a code.

Practical cryptanalysis has even been acknowledged at the highest level. The source is none other than Nikita Sergeyevitch Khrushchev. While sightseeing in Los Angeles with U.S. Ambassador to the U.N. Henry Cabot Lodge during his 1959 visit to the United States, the Soviet Premier boasted that he had seen a message that President Eisenhower had sent to Prime Minister Nehru of India about border troubles with Red China, as well as a message to Eisenhower from the Shah of Iran. Earlier, in Washington, he remarked to C.I.A. chief Allen Dulles that C.I.A. agents gave their codebooks to the Russians, which the Soviets used to feed false information to the C.I.A. and to demand and receive money. He suggested that the U.S. and the U.S.S.R. save money by pooling intelligence services.

The dreaded change of code, which would have cost the United States her best source of information just as it was needed more and more, now seemed inevitable. But morning after morning, the messages bore the same aspect and continued to break down under the same treatment. After days of anxious waiting, Navy cryptanalysts read a cable from Tokyo to Mexico on June 23, warning the legation: “There are also some suspicions that they [the Americans] read some of our codes. Therefore, we wish to exercise the utmost caution in accomplishing this mission.”
Was this to be the extent of the Japanese security precautions? It seemed incredible, yet it appeared so. The cryptosystems continued unchanged. The Foreign Office capped its ludicrous cryptosecurity program of pointless warnings and regulation changes with a step that was almost as effective as the others: on November 25, it directed its embassies to print “Kokka Kimitsu” (“State Secret”) in red enamel on the right of the number plate of their cipher machines. Perhaps they thought that this incantation would prevent cryptanalysis as an amulet was supposed to ward off sickness!