The Codebreakers: The True Story of the Secret Intelligence Team That Changed the Course of the First World War (38 page)

When the AFDGX cipher first appeared on 5 March, it did indeed seem as if the Germans had conquered the French cryptologists. Painvin worked logically through different strategies to decipher AFDGX, failing at them all while the head of the Bureau du Chiffre, Colonel François Cartier, looked over his shoulder pessimistically observing, ‘This time I don’t think you’ll get it.’

Painvin had to get it. Direction-finding equipment showed the Allies that the messages were flowing between the Germans’ top levels of command: divisions and army corps. This meant they were the overarching messages of attack. On 21 March, at 4.40 a.m., 6,600 German guns unleashed a hellish barrage against the British Fifth Army on the Somme – and the right wing of the British Third Army further north near Cambrai, a worse thunderstorm of artillery than the British had inflicted on them when the Battle of the Somme began in 1916. Five hours later, 62 German divisions – of about 15,000 men each – surged forward along the nearly 50-mile front between Arras and La Fère, and by 5 April had penetrated 38 miles into the Allied lines.

In a war whose gains and losses were measured in yards, the profound shock struck to the core of Allied intelligence. The reeling head of the
Deuxième Bureau
at France’s GHQ said: ‘by virtue of my job I am the best informed man in France, and at this moment, I no longer know where the Germans are. If we’re captured in an hour, it wouldn’t surprise me.’

The Allies retreated to Amiens, and staunched the German assault. As the Germans requested more artillery support, they generated more messages, giving Painvin more codebreaking ammunition. Painvin worked like a man staring death in the face to crack the cipher. By the beginning of April, after working 48 hours straight, he had solved the AFDGX. But the Germans kept changing it, forcing Painvin to keep pace. By working through old messages from April and May, he was able to create the German code key they had used for their March offensive. By late May, he could use this key to break the current codes.

But the situation had moved from dire to desperate. The German stormtroopers had pummelled their way another 30 miles south, and were now just 40 miles from Paris, which they were shelling with a terrifying new weapon. The ‘Paris Gun’, which with its range of 75 miles and its 100-foot barrel was so large it had to be mounted on railway cars, had rained shells seemingly from out of nowhere down in front of the Gare de l’Est, by the Quai de la Seine, and in the Jardin des Tuileries. On Good Friday, one of its 234-pound shells had landed on the roof of the St-Gervais-et-St-Protais church while a Mass was in progress, killing 88 people and wounding another 68. In all, the Paris Gun killed 250 Parisians and wounded 620, its fatal shell reaching an altitude of 25 miles at the highest point in its trajectory. It was the greatest height yet attained by a weapon of war, one requiring the gunners to calculate the rotation of the earth before they fired. For the first time in history, death came down on humanity from the stratosphere.

As if that wasn’t enough pressure on Georges Painvin, on 1 June the Germans added another letter to their fiendish code. The AFDGVX cipher was now in play, and yet within 24 hours Painvin had solved it. The challenge now was to intercept the message that revealed where the next attack would be launched.

At around 9 p.m. on 1 June, the French listening post at Mont-Valérien intercepted a message that according to direction-finders had been sent from German HQ to its 18 corps. The message read: ‘Rush munitions Stop Even by day if not seen.’ The Germans were desperate, moving arms by daylight if they could to Remaugies, and now the Allies could plan on how to counter them there. When 15 German divisions attacked on 9 June, they only advanced six miles before being repelled by five French divisions. The French called the deciphered message – thanks to Painvin – ‘La Radiogramme de la Victoire’.

Painvin’s codebreaking had not won the war. But he had stopped it from being lost. And now the AEF was reaching strength and about to enter the fight – with a secret code weapon that no amount of code-logic could teach, or break.

The US army had marched off to war with three authorised code and cipher systems, none of them inspiring confidence in the Allies. The Telegraph code was a fragile system designed for headquarters communications; the Signal Corps had created a highly flammable celluloid device called the Army Cipher Disk, but it was a simplistic tool for mono-alphabetic substitution, the kind of elementary code-making that uses a fixed alphabet where letters are substituted for other letters – for example, a = z, b=y, and so on – and which can easily be solved by analysing the frequency of letters and corresponding them with the frequency of likely letters in the original language (for example, in English, the letter ‘e’ would appear most frequently in whatever its substituted form).

The British taught the Americans how to use the Playfair cipher, which had been in use since the mid nineteenth century and which replaces pairs of letters in plain text with pairs of letters in cipher text. While far more complicated than mono-alphabetic substitution, it too could be solved with frequency analysis, but the point was to give the Americans a crash course in code creation. The British and French also provided the Americans with obsolete code books to show them how it was done, with the result being the first American Trench Code in 1918, containing 1,600 words and phrases designed to be used with ‘super-encipherment’ – enciphering a message more than once. The Trench Code was used for training only, and was never sent to troops on the front lines for fear of capture.

The US quickly needed its own set of codes that could be easily used by operators in battlefield conditions, and yet which were secure enough to confound the Germans. They devised the River codes, a series of two-part codes, separated into encoding and decoding, named after great American rivers, which were issued to front-line forces in August 1918.

Despite the American soldier’s casual use of
en clair
communication when speaking to colleagues on field telephones, a common offence that drove commanders and cryptanalysts to distraction, the US soon stumbled on a code so secure that not even their best cryptanalysts could break it: the mother language of the army’s aboriginal soldiers.

Solomon Bond Louis was underage when he volunteered to go to war for a country that didn’t even consider him a citizen – and wouldn’t until 1924. As a member of the Choctaw Nation, Louis hailed from an aboriginal group that had been moved from its ancestral homes east of the Mississippi River to the flat, hot scrub of Oklahoma by the Indian Removal Act of 1830, which opened up the lush homelands of the five ‘Civilised Tribes’ in Louisiana, Georgia, Florida and Alabama to European settlers.

Louis attended Armstrong Academy in Bryan County, Oklahoma. Like so many soldiers of the Great War, when he saw his older friends joining up, he wanted to go with them. So he pretended to be 18 years old, and after basic training that saw the aboriginals prepare for war with sticks simulating rifles (so too did African-American soldiers), he wound up with 17 of his fellow Choctaw soldiers in the 36th Division, going to the Western Front on 6 October 1918.

Leader and Bond and their fellow Choctaw would indeed turn the tide via a dynamic intersection of old world and new. For the AEF command to communicate with troops in the front lines, the US army overwhelmingly preferred the telephone. Switchboards were built underground at division headquarters to withstand enemy shelling, and in order to release men for the front lines, the AEF recruited 200 French-speaking female telephone operators from commercial telephone companies to serve overseas as civilian members of the Signal Corps Female Telephone Operators Unit, known to all who dealt with them in their postings from Chaumont to Paris to London as the Hello Girls.

For troops in the field, phone lines were strung on four-foot stakes or run along trench walls from the switchboards to each infantry battalion, and they also linked adjoining battalions. As Colonel A. W. Bloor, commander of the 142nd Infantry Regiment later explained in a memo to the division’s commander: ‘The field of rocket signals is restricted to a small number of agreed signals. The runner system is slow and hazardous. TPS [
telegraphie par sol
– driving iron poles into the ground to pick up electrical currents by means of induction] is always an uncertain quantity. It may work beautifully and again, it may be entirely worthless. The available means, therefore, for the rapid and full transmission of information are the radio, buzzer and telephone, and of these the telephone was by far the superior – provided it could be used without let or hindrance – provided straight to the point information could be given.’

The Germans – like the Allies – would tap into phone lines to listen in on conversations between the front and command, and civilian soldiers, such as those conscripted into the AEF, didn’t always appreciate the need to use code when transmitting messages: it was more complicated than anything they had been used to in civilian life, it took longer, and under extreme conditions, time was always of the essence.

On 8 October 1918, the 36th Division was part of a fresh Allied attack, supported by artillery fire. As they captured German positions, the Americans noticed that the Germans had left their communication lines uncovered, as if tempting the Americans to use them. So they did so in a way that the Germans – and even the Americans – had never imagined.

The origins of how the Choctaw became the US army’s code-war weapon vary from a white American officer stumbling upon them conversing in their own language to someone at HQ remembering that they had aboriginals in uniform, but far more likely is the claim from the men who were there that the Choctaw themselves suggested that they might be able to help out. Despite the team of highly-educated codebreakers who pushed their formidable intellects to the edge to decode the enemy’s plans, the Choctaw brought something that no codebreaker could penetrate: their ancient language. The AEF quickly agreed, and the Choctaw were soon relaying messages over the phone in their native tongue.

As the Choctaw language had not evolved with the exigencies of mechanised warfare in mind, some improvisation was necessary. ‘Big gun’ was used to indicate artillery, while ‘little gun shoot fast’ meant machine gun. The battalion numbers were indicated by one, two and three grains of corn, and the regiment itself was referred to as ‘the tribe’. The Germans were utterly confounded, having no idea what this new code was, and no way – with their Eurocentric dictionaries – to break it. When a captured German asked, ‘What nationality was on the phones that night?’ he was told only that it was Americans who had been on the phones.

Within 72 hours of taking code command, the Choctaw had demonstrated their value in helping the Americans succeed in that October attack. The war was far from over, but thanks to another colonised group of soldiers and their field-code ingenuity, it would be soon.

The man who would lead the push to victory for the Allies was a pear-shaped insurance salesman with a high-school diploma who had embezzled regimental funds, but Sir Arthur Currie was also a fine military mind that also knew its own limitations. Which was why he believed in intelligence.

Arthur Currie had begun his life at arms in 1897, aged 22, at the lowest rank of gunner in a militia regiment in Victoria, Canada. By the time war broke out, his skill as a marksman, his absorption of military strategy and history through books and manuals and courses, and his reputation for discipline had earned him promotion to brigadier general and command of the Canadian Expeditionary Force’s 2nd Brigade.

Currie went to war burdened by a crime. He had used the profits from his successful insurance business to speculate in real estate during a land boom on Canada’s Pacific coast. When the boom went bust, Currie was land rich and cash poor, and so he borrowed $10,000 of regimental funds to cover his debts, on the understanding that the regiment’s honorary colonel was going to underwrite the regiment to the tune of $35,000. When he did not, Currie had become an embezzler, and it wasn’t until 1917 – after Canada’s prime minister Robert Borden learned that the man who would lead the Canadian army to glory was one step away from jail – that his own officers loaned him the money to resolve the theft. Indeed, such was the concern about this matter at the highest levels of Canadian government that Currie almost didn’t win the command, and the final months of the war could have taken a much different turn for the Allies.

Currie, a lively wit when among his officers, appeared stiff and stern to his men, a six-foot-two, overweight taskmaster whose lack of military bearing was made even more apparent by his refusal to sport a moustache. But he cared deeply for his men, and planned every attack with their lives in mind, having learned at the Battle of Festubert in 1915 what havoc could result from poor planning and poor intelligence. Sloppy strategy thanks to commanders in the rear saw Currie’s brigade lose 1,200 men in the course of just a few days.

In August 1918, Arthur Currie had both a knighthood and command of the Canadian Corps, a 100,000 strong force that, until his elevation in June 1917, had always been commanded by British officers. The massive German surge of March had been repelled, but the Canadians had been stationed in quiet sectors and had avoided most of the fighting. As a result, they were fresh and well trained in their battle plan when Currie launched the assault from 10 miles east of Amiens on 8 August 1918. It would be the beginning of a period known as ‘The 100 Days’ but for the young nation of Canada, they took those 100 days as their own particular triumph.

The war that had been dug into a spider’s web of trenches across the muddy, cratered Western Front was, in its final phase, a largely fast-moving operation that put heavy demand on fast-moving intelligence. The Canadian Corps had learned much from their French and English colleagues, and now, by necessity, they had to improvise and innovate when it came to battlefield intelligence to keep pace with their astonishing progress.