100 Years Ago: The Birth of the SIGINT Century, Part I

Yesterday The Wall Street Journal reported, based on high-level leaks, that the U.S. Intelligence Community (IC) has been intercepting the communications of Syrian President Bashar al-Assad and, moreover, this important intelligence source has been providing valuable information about that regime, but also about its enemies, namely the Islamic State, with whom Washington, DC, is presently at war, albeit not very effectively.

Although it is rare that the public gets a glimpse at how the IC actually works in this manner, none of this story surprises anybody acquainted with the real world of intelligence. Of course the Assad regime is talking a lot internally about its enemies, and some of that information may even be accurate. The U.S. is heavily dependent on signals intelligence (SIGINT) to understand what is happening in Syria because that war-torn country is something of a denied area for traditional espionage, as American case officers running around Syria would likely soon be captured and butchered.

Yet, in truth, the U.S. Government is always heavily dependent on SIGINT, which for decades has been the bulwark of American espionage, providing something like eighty percent of the actionable intelligence the IC delivers every day to decision-makers, military and civilian. Hence the damage wrought by the Snowden Operation is a source of serious concern far beyond Washington, DC, given how important intelligence-sharing is to many key U.S. allies. Although Snowden’s blow to the National Security Agency and its international partnerships is unprecedented, NSA continues to do its job, providing the lion’s share of American intelligence, day in and day out.

SIGINT has been the most important form of intelligence in the world for exactly a century. The interception of messages for intelligence purposes has existed pretty much as long as there have been written messages. For millennia these were carried by mail and dispatch riders, and much effort was put into intercepting and decrypting them, since important messages have been written in secret code for centuries. By the Enlightenment, any state that wished to survive had its own Black Chamber, staffed with code-breakers who specialized in reading the purloined secret messages of rival states; Austria’s was considered the best in the eighteenth century, while royal France was highly proficient here also.

The invention of the telegraph pushed things forward, and by the middle of the nineteenth century states had a cost-effective way of sending messages quickly, thanks to Morse code, and rivals naturally tried to access these messages surreptitiously. However, this could be a challenge, as the telegraph cable had to be physically tapped, preferably without the owner knowing it.

The real revolution in communications that birthed SIGINT as we know it today was the invention of what was termed wireless telegraphy — we would call it radio — at the turn of the twentieth century. The military implications of this new technology were obvious, as were its vulnerabilities: anybody could intercept messages out of the ether, not just the intended recipients. In the decade before the First World War, navies in particular developed doctrines on how to use radio, including codes and ciphers to protect messages. For navies, this was a huge step forward in communications, a revolution without precedent in naval history, as any country that had sufficient radio relay stations — here colonial powers had an advantage — could stay in touch with their ships anywhere they sailed, enabling a degree of operational coordination that Nelson could never have dreamed of.

Most European armies, however, were slower to embrace radio before 1914, mainly because they liked what they already had to communicate, telegraph and telephone transmitted via landline, which were more secure than radio, plus a proven technology. Radio was expensive by comparison and untried. Most armies believed that, in event of war, their advancing forces would be able to lay enough new wires to stay in touch with their commanders in the heat of battle. Like so many ideas held by military minds before the First World War, this turned out to be an illusion.

But first, the war at sea. All Europe’s major navies entered the First World War with radio systems and doctrines that employed codes and ciphers to protect their communications. Through what is termed traffic analysis (TA), anybody listening could learn some important things about ships sending encrypted messages, thanks to message externals, and radio is always vulnerable to direction-finding (DF, the practice of triangulating a signal from multiple intercept sites to determine the sender’s location). While all that matters, it was not what intelligence officers wanted — the decrypted text of the original message.

Here fortune played a role, as it always does in war. On 26 August, less than a month after the war began, the German cruiser Magdeburg was conducting a reconnaissance sweep close to Russia’s Baltic Sea coast — too close, as it turned out, since her skipper ran her aground off what is today Estonia (see left). After a brief fight, the Magdeburg surrendered. Among the captives taken by the Russians included several secret codebooks: these were supposed to be tossed over the side in weighted bags to send them safely into the deep, which was hardly an option when her skipper ran the cruiser on the rocks in a few feet of water.

Russian naval intelligence, still in its infancy with radio, wasn’t quite sure what to do with these codebooks. In a momentous decision, they decided to share one of the codebooks with their British allies. This document arrived in London on 13 October, amid much secrecy, being delivered to Winston Churchill, the civilian head of the Royal Navy, who promptly turned it over to the man who knew exactly what to do with it.

He was Captain (later Admiral) Reginald Hall, known as Blinker for his pronounced facial tic, an old sea
dog who turned out to have a gift for espionage (see left). Appointed head of the Royal Navy’s intelligence division in October 1914, Hall established a super-secret office, colloquially known as Room 40 from its original location in the Admiralty in London. Here, behind tightly closed doors, British naval personnel began cracking encrypted German messages. They were helped by Britain’s cutting of all Germany undersea telegraph cables in the war’s first week, which forced Berlin to use radio, which was easily intercepted.

Hall was a good talent-spotter, and he assembled in Room 40 a motley crew of sailors, mostly new to the service, among them classical scholars, mathematicians, polyglots, and assorted adventurers who were not well suited to life in the peacetime navy but were talented at the arcane art of cracking codes. Here the codebook from the Magdeburg proved an enormous gift. It did not give away all German naval ciphers, but it was a good “crib” to start, and when bolstered by more codebooks captured from other German ships lost at sea, Room 40 was able to gain access to a high percentage of Berlin’s encrypted naval communications — a breakthrough that remained a closely-held secret throughout the war. Most importantly, the Germans never realized their communications had been compromised.

For Britain, Room 40’s success gave several decisive advantages that proved to have strategic importance. In the first place, it meant that the German navy could not launch a bolt-from-the-blue attack on the Royal Navy, London’s greatest fear, since Hall’s codebreakers had advanced warning of any major German naval movements before they happened. Just as important, Room 40’s prodigious intelligence output allowed Britain to enforce the distant blockade against Germany that, in the end, was the single greatest factor in the defeat of the Central Powers. Armed with SIGINT about which neutral merchant vessels were carrying contraband, the Royal Navy wrought havoc on blockade-runners, slowly strangling Germany’s vast economy.

Hall’s single greatest triumph, however, came thanks to Room 40’s success against diplomatic ciphers. This was the infamous Zimmermann Telegram, the January 1917 secret German message that offered Mexico its “lost provinces” of the American Southwest if they agreed to enter the war on Germany’s side. The message was obtained through subterfuge, and via cunning methods it was shared with the Americans. Hall understood that the resulting outrage would allow President Woodrow Wilson to overcome American reticence, including his own, and enter the conflict on the side of the Allies, who desperately needed American help to stave off defeat. And so it did: on 6 April, the United States entered the Great War, ensuring ultimate Allied victory. From that point, the defeat of the Central Powers became an issue of when, not if.

Room 40’s SIGINT triumphs under Hall’s leadership — he would head British naval intelligence until 1919 — enabled every other kind of intelligence, including human intelligence (HUMINT) and particularly counterintelligence. Intercepted German messages by Room 40 led to breakup of the espionage-sabotage network led by Franz von Rintelen, a naval officer and spy who had conducted terrorist bombings in the neutral United States, including the notorious Black Tom bombing of July 1916, to disrupt the delivery of war materials to Britain.

Room 40 did not cease operations once the war was won. For London, its espionage acumen would prove as important in peacetime as in war. It was rolled, together with British Army codebreakers, into the euphemistically named Government Code & Cipher School (GC&CS), the organization that would deliver the great ULTRA secret of the Second World War. In 1946, GC&CS was rebranded as Government Communications Headquarters (GCHQ), as it remains today, perhaps NSA’s closest intelligence partner and a bedrock of the Anglosphere SIGINT alliance that was cemented in Allied victory over Hitler.

GCHQ, like NSA, has been damaged by the Snowden Operation, which shows every sign of being a deliberate Russian intelligence scheme to harm its enemies. As the direct descendant of Room 40, GCHQ continues to provide British and Allied decision-makers with unsurpassed intelligence to prevent wars whenever possible, and to win them should that become necessary. Every day they help thwart spies, saboteurs, and terrorists. The dominance of SIGINT in global intelligence is nothing new, in fact it is now exactly one hundred years old. Given the increasing dependence of governments, groups and individuals everywhere on electronic communications of a diversity and complexity that Blinker Hall could never have imagined, the dominance of SIGINT in the world’s never-ending secret espionage game seems unlikely to change anytime soon.

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