US President Barack Obama embracing German Chancellor Angela Merkel. Photo: Reuters
IT WAS not news to the Indonesian government, or to Germany's Angela Merkel, that the privacy of their telephone or computer communications has long been compromised - by Australians, Brits, Japanese and Chinese spies.
They know this, and as long as no one reminds them of this humiliation, everything is fine and they use simple security - of the sort that's available to anyone - to avoid giving anything away. But open reference to it must involve affected alarm, appeals for explanations, and affected acceptance of whatever ambiguous reassurances they can get.
A particularly naive American statesman, Henry Stimson, was shocked in 1917, after the US belatedly discovered there was a world war going on, to learn that a section of his War Department was decoding and decrypting messages sent between other countries and their diplomats, agents and spies. He ordered it be stopped. Gentlemen, he famously said, do not read each other's mail.
But the British and Germans were not gentlemen. Indeed, US entry into the war was facilitated by the helpful delivery by British intelligence to US President Woodrow Wilson of a German message to Mexico offering an alliance with Germany if the US entered the war on Britain's side. The so-called Zimmermann telegram got the Americans to France just in time to help dictate peace terms to Germany.
The Brits did not want the US to know they could (and did) decode every single message going by cable across the Atlantic Ocean. They were reading US codes too. So they devised an elaborate cover story to explain how they got and could read the telegram. That this story was false later led conspiracy theorists to think the very telegram was concocted by the British, but this, most think, was not so.
The British, French and Poles were particularly good at code-breaking, as were the Soviet Union and Germany. Combined efforts to break codes - even those devised by machines, such as Germany's Enigma machines (first cracked by the Poles, who passed on the secret to France and Britain) - involved a good deal of what mathematicians called ''brute force'' - constant and repetitive attempts with different combinations, along with any available clues or short cuts. These efforts laid most of the framework for the development of computers.
Code-breakers at Bletchley, near Oxford, broke some of the many German codes and were sometimes able to read others, depending on German security breaches. Pattern analysis of radio traffic could also show something was going on merely by changes to the volume or type of messages.
Lessons learnt from this were used in deception operations. Before and after D-Day, for example, a fake US Third Army sent thousands of messages to and from phantom officers, leading the Germans to think a large attack was coming later and from elsewhere.
Likewise, Americans and Australians deciphered much Japanese traffic. The Russians were also adept at code-breaking. As a consequence, they had very secure codes of their own. The Germans, too, had more success than anyone realised for a long time. Germany also pioneered use of the often quite insecure codes of low-level allies to get a look over the shoulder of more secure enemies.
Britain, for example, gave the US considerable access to high levels of military and government thinking, even before the US entered the war. But then it discovered that much of what the Americans were told was being ''read'' by Germans because of the low calibre of American codes (which Britain had also long been reading).
When the US entered the war, Britain shared its expertise and technology, but also some of its black-book methods. If one realises, for example, that the other side is reading their traffic, the answer is not necessarily to upgrade codes. One can instead use it as a channel for disinformation, while steering genuinely sensitive material elsewhere.
These days, some nations consciously send messages - false or meaningful - to others by exchanging notes in low-calibre diplomatic codes, which they know can and will be broken. An intelligence analyst reading an apparently confidential message from another country's embassy to its capital is more likely to think it truthful, or to show what they really think.
It can be more or less taken as read that virtually any electronic signal is being ''read'' by others. Nowadays, there's so much traffic - even with ''filtering'' by computers - it's possible that important information is missed until it's too late. That has been a problem of the war against terror.
But most of the systems were developed during the Cold War, when British, American, Canadian, and even Australian, wireless centres were routinely sweeping up electronic signals, particularly from inside the Iron Curtain. Surveillance of Russian radio traffic began during World War II, but no amount of effort could decipher much. Soviet espionage in Australia gave the US its first good look-in.
An Australian, almost certainly Ian Milner of the then Department of External Affairs, passed on to Russians a confidential British assessment of how the security situation would look in south-east Asia and the Mediterranean after the war against Japan. The Soviet embassy enciphered and telegraphed the document to Moscow. Americans recorded the message as it was being retransmitted across China, but, as usual, they could not decipher it.
As part of a pragmatic appeasement of Japan, with whom Russia was not then at war, Russian spymasters decided to leak the assessment to Japanese diplomats, who promptly encoded it in their own codes and sent it off to Tokyo, mentioning its provenance in Australia. The similarity of the message length was immediately apparent to American cryptographers, who could read the Japanese traffic and were thus ''given'' a key into the Soviet encipherment system.
A top-secret US operation, called Venona, lasted another 25 years, as Americans built on this key to penetrate Soviet espionage around the world, such as by ''atomic'' spies, Julius and Ethel Rosenberg.
These days, the computer has levelled some of the playing field, even if, in the old Western alliance, a group of English-speaking countries - America, Britain, Australia, New Zealand and Canada - have the greatest concentration of resources, including satellites and geographic coverage.
But other nations, friendly and unfriendly, are hardly unaware of what can be, and is done, or how easily surveillance for military or security intelligence can be diverted for use in commercial espionage or mischief-making. And much of the world's cyber warfare - probes by nations such as Russia, China and Iran to penetrate defence, business and government computer systems in other countries - is now managed by people hostile to the West.