Jerry Roberts, the last surviving member of the British code-breaking team that cracked strategic ciphers between Hitler and his top generals, helping to hasten the end of World War II, died on March 25 in Hampshire, England. He was 93.
His death was confirmed by the Bletchley Park Trust, a nonprofit group that administers the Victorian estate north of London where the British government lodged Mr. Roberts and hundreds of other code breakers during the war, among them linguists, mathematicians and puzzle masters of various backgrounds.
Mr. Roberts, a German linguist, was part of a small top-secret group assembled in 1941 to help decrypt messages picked up in radio signals between Hitler and his field marshals on the front. The team’s very existence remained a secret until 2006, when the British government declassified wartime intelligence files.
By 1941, Bletchley Park cryptographers had already deciphered thousands of messages transmitted by lower-level German commanders in the field, thanks to the work of the mathematician Alan Turing, who in 1940 cracked the daunting German secret code that the British called Enigma. But they were stumped by the even more complex ciphered messages being transmitted among Hitler and the generals Erwin Rommel, Wilhelm Keitel, Gerd von Rundstedt and Alfred Jodl.
Code breakers initially called the system Fish, taking the name from a German code operator who, in an unguarded moment, had referred to the code as “sägefisch” (sawfish). Mr. Roberts and his group nicknamed it Tunny — as in tuna fish — and they were able to crack it.
Mr. Roberts eventually served as the head cryptologist for the team, which grew to more than 100.
The messages the team deciphered enabled the British government to warn Soviet leaders in 1943 about a major German offensive planned at Kursk that summer. The Soviet Army’s repulse of the attack in the Battle of Kursk was a turning point of the war.
The Tunny code breakers later helped set the stage for D-Day, establishing in the weeks before June 1944 that Hitler and his commanders expected an Allied invasion along the French coast at Calais, preceded by a feint at Normandy. The Germans were caught off guard by the full assault at Normandy.
Like the Enigma code, the Tunny code was produced by an encrypting machine that used a formula to transform words, one letter at a time, into corresponding cipher-symbols. They were then scrambled repeatedly by electrical rotors that could change the pattern, or “key,” of each cipher an almost infinite number of times. (The Enigma code had been produced by a machine with four rotors; the more complicated Tunny code employed a machine with 12, Mr. Roberts said.)
As long as the German wireless operator at each end of the message used the same machine, and each machine made the same pattern of almost infinite changes, the message was decipherable.
Figuring out the logic in the Germans’ nearly flawless ciphering system was “a miracle,” Mr. Roberts was quoted as saying. Its only flaw, he said, was in requiring human operation. “We owe the breaking of the code to the errors of German operators,” he said in a 2006 speech.
German operators erred egregiously several times, he said, by sending encrypted messages twice in exactly the same way, violating a requirement that they reset the machine’s ciphering code for each message. This gave the British analysts a rich field of material to study, he said.
Advertisement
The Germans’ other mistake was to exchange chitchat in Tunny. British cryptographers gleaned a lot, for example, when a German operator at the Russian front said “Cold!” in Tunny, and when an operator in Italy attested to the “murderous heat.” The context of such transmissions helped them understand the coded language. (Another commonly overheard German message was, “I’m so lonely.”)
“It’s very difficult to explain how to break messages,” Mr. Roberts told an interviewer. “Even when you had good knowledge of the German language and the skill, you still needed a kind of knack.” The trick, he said, was to “follow that instinct.”
Raymond Clarke Roberts (known as Jerry from childhood) was born on Nov. 18, 1920, in Wembley, in northwest London. His father was a pharmacist, his mother the organist in a church. He studied German and French at University College in London. His ambition was to join the Foreign Office.
After the war broke out, Mr. Roberts said, his German professor, Leonard Willoughby, who had been a leader of the Admiralty’s code-breaking unit in World War I, asked if he might be interested instead in “work of a secret kind.” Mr. Roberts, a civilian, joined the British intelligence agency and was given the rank of captain for the duration of the war.
Mr. Roberts is survived by his third wife, Mei Li, and two daughters and a son.
After leaving government service, Mr. Roberts founded a research and marketing company, which he sold in 1993.
In an interview with The Telegraph, he conveyed the excitement code breakers experienced when deciphering strategic information, and the frustration they felt at having to keep their work secret. When sharing the information with allies, British intelligence always attributed it to “spies.”
“I can remember myself breaking messages about Kursk,” Mr. Roberts recalled. “We were able to warn the Russians that the attack was going to be launched, and the fact that it was going to be a pincer movement. We had to wrap it all up and say it was from spies, that we had wonderful teams of spies.”
No comments:
Post a Comment