Layout 8 - Winston Churchill

SIGSALY...voice-scrambling system developed for its commercial telephoneusers by AT&T. Based on 1920s analog technology,it was not nearly secure enough for communicating militarysecrets. 2Well aware of A-3’s shortcomings, American andBritish signals experts insisted that the voice link only beused with carefully controlled code words, so as not toreveal pending plans and operations to enemy listeners.Many senior commanders who telephoned often forgot thewarning, only to be reminded by a censor interrupting theircall. In a March 1942 memo to Churchill’s senior staff, theCabinet Secretary, Sir Edward Bridges, warned of thedangers of unguarded reliance on transatlantic radiotelephoneservice. 3The fame of Bletchley Park obscures the fact that theenemy was listening, too, and also had its technical wizards.Germany’s Deutsche Reichpost had established a listeningstation on the Dutch coast by early 1941. GermanIntelliegence developed technical means to detect Alliedtransatlantic signals, and eventually could decode theircontent as they were being sent. Captured records at theend of the war showed just how good the enemy listeningactivity was: The Germans had recorded complete transcriptsof many calls between senior Allied military figures,and even some between Churchill and Roosevelt. 4The telephone nevertheless remained in usethroughout the war because it was simply indispensable,being available at all hours. Censors closely monitoredwhatever anyone, Churchill included, might say on the line.AT&T, understanding the limitations of its A-3scrambler, began seeking a better system as early as 1936.Though many schemes had been patented, none providedabsolute security. In New Jersey, the Bell Laboratoriesresearch team, headed by A.B. Clark, focused on developinga way to turn voice signals into digital data—this at a timewhen digital technology was more theoretical than practical.Homer Dudley, a Bell research physicist, eventuallycreated a “Vocoder” (voice coder) device to convert analogvoice sounds into digital signals while preserving “some”voice quality. An early prototype was demonstrated at the1939 World’s Fair. Research on a viable transmission systemwas initiated as “Project X” in 1940. 5Shortly after the Japanese attack on Pearl Harbor andAmerica’s entry into the war, Bell technicians demonstratedtheir system to the U.S. Army Signal Corps. The Armyissued a contract to build the two trial devices. The firstprototype was completed in August 1942. 6 Its manufacturingpriority was high and security was extremely tight.Indeed, only after high-level negotiations was Bletchley Parkcomputer authority Dr. Alan Turing allowed even to see thedevice, and report his evaluation to Churchill in London. 7As confidence in its ability grew, six terminals had beenordered by late 1943.FINEST HOUR 149 / 32Joys of the Scrambler:Fitzroy Maclean and the PMAn American WAC sergeantexplained that our conversationwould be scrambled,and that we could speak freelywithout fear of being overheardby the enemy. Mr. Churchill’swell-known voice soon camebooming over the ether.“Have you spoken to Pumpkin?”“Pumpkin, Prime Minister? I’m afraid I don’tunderstand what you mean.”“Why that great big general of mine. Andwhat have you done with Pippin?”There was a pause, interrupted only by theinhuman wailing and crackling of the ether.Then, projected over the air, from DowningStreet to Washington, and then back to NorthAfrica, came quite distinctly an exclamation ofhorror and disgust.“Good God, they haven’t got the Code!”A few moments later the Prime Ministerwas back on the air. Shall we scramble?” heasked gaily.“I’m afraid, Prime Minister, that I amscrambled.”There was a rumbling noise, followed bysilence, and Mr. Churchill’s voice came throughagain: “So am I.”After which, much to my relief, we wereable to talk normally…though he continued torefer to Field Marshal Wilson, a rather portlyofficer, as “Pumpkin” and to his son, Randolph,as “Pippin.” The two pseudonyms seemed togive him the greatest pleasure.Having laid down the receiver with reliefafter this unnerving experience, I started up thestairs of our dugout but then turned back tocollect something I’d forgotten. As I opened thedoor, I was startled to hear my own voicecoming through it.“Pumpkin, Prime Minister?”….The prettyAmerican sergeant wasplaying our conversationback to herself, rockingwith laughter. “And in anEnglish accent, too,” Iheard her say.—Sir Fitzroy Maclean, ChurchillTour Dinner, Strachur, Scotland,12 September 1987, Churchill Proceedings 1987