How did the zimmerman telegram affect ww1
Zimmermann Telegram | Facts, Text, & Outcome
Zimmermann, Arthur: Zimmermann Note
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Zimmermann Telegram, also called Zimmermann Note, coded telegram sent January 16, 1917, by German foreign secretary Arthur Zimmermann to the German minister in Mexico. The note revealed a plan to renew unrestricted submarine warfare and to form an alliance with Mexico and Japan if the United States declared war on Germany. The message was intercepted by the British and passed on to the United States; its publication caused outrage and contributed to the U.S. entry into World War I.
The U.S. and the German U-boat campaign
The sinkings of the Lusitania (May 7, 1915) and the Sussex (March 24, 1916) by German U-boats had brought the United States to the brink of war with Germany. American neutrality was preserved only by the adoption of the so-called Sussex pledge (May 4, 1916), which obliged German submarine captains to precede the torpedoing of merchant or passenger ships with a warning and to provide for the safety of passengers and crew of sunken ships in the wake of such attacks. In time this policy came to be seen as impracticable by the German military, and the views of commanders such as Paul von Hindenburg and Erich Ludendorff prevailed over those of the chancellor, Theobald von Bethmann Hollweg, who had previously blocked the adoption of extreme measures in the German naval campaign.
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On January 9, 1917, Bethmann, Ludendorff, and Hindenburg met at Pless Castle in Silesia (now Pszczyna, Poland) to discuss the resumption of unrestricted submarine warfare against all merchant shipping, neutral as well as belligerent. Bethmann was tasked with allaying the concerns of U.S. Pres. Woodrow Wilson in an attempt to preserve American neutrality for as long as possible. However, all three men at the Pless conference agreed that American participation in the war had to be regarded as a strong likelihood, regardless of the chancellor’s efforts. Bethmann had informed the European neutrals—Switzerland, the Netherlands, and Denmark—of Germany’s peace terms and had received a positive response. He took the same proposal to Wilson and appealed to him to persevere in his peace efforts. However, this message, delivered to the State Department on January 31, was accompanied by a notice of the all-out submarine warfare campaign that was scheduled to begin the next day.
Wilson was reluctant to break diplomatic relations with Germany, but, yielding to public clamour and senatorial advice, he severed those ties on February 3, 1917. While announcing the break in a speech to Congress, he voiced the fervent hope that the Germans would not, by sinking American ships, compel the United States to adopt belligerent measures.
German submarines avoided attacking U.S. ships throughout February 1917, and American sentiment remained strongly pacifistic. However, Wilson’s cabinet, a large portion of the press, and numerous public leaders demanded that the U.S. government arm its merchant ships for self-defense. Agreeing that armed neutrality was the only safe policy in the circumstances, Wilson, on February 26, asked Congress for the power to arm merchantmen and take all other steps necessary to protect American commerce.
Zimmermann, relations with Mexico, and the end of American neutrality
A crucial turning point in both Wilson’s own thought and in American opinion occurred following the receipt and publication of the so-called Zimmermann Telegram.
Arthur Zimmermann had succeeded Gottlieb von Jagow as Germany’s secretary of state for foreign affairs in November 1916. Jagow had resigned in protest over the proposed resumption of unrestricted submarine warfare, and Zimmermann, who was seen as amenable to the policy, was selected to replace him.
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On January 16, 1917, Zimmermann dispatched a secret message to the German minister in Mexico, Heinrich von Eckhardt. It instructed Eckhardt to propose a Mexican-German alliance should the United States enter the war
on the following basis: make war together, make peace together, generous financial support, and an understanding on our part that Mexico is to reconquer her lost territory in Texas, New Mexico, and Arizona.
Because the British had severed the direct undersea telegraph links between Germany and North America in the earliest days of the war, Germany was forced to route sensitive diplomatic traffic through neutral countries.
Zimmermann’s coded message was thus transmitted through the American embassy in Berlin before passing though London and finally arriving at the U.S. State Department in Washington, D.C. The telegram reached the German embassy in Washington on January 19, and it was transmitted to Eckhardt in Mexico later that day. Unbeknownst to Zimmermann, his message had been intercepted along the way and decoded by the British Admiralty Intelligence, and its contents were communicated to Wilson.
Zimmermann’s proposal seemed outrageous on its face, but Mexico had encouraged the German overture, as Mexican relations with the United States had deteriorated rapidly after Wilson’s grant of de facto recognition to Venustiano Carranza’s revolutionary government in October 1915. Carranza’s rival, Pancho Villa, raided Columbus, New Mexico, on March 9, 1916, in order to provoke a crisis between Mexico and the United States. Wilson sent a punitive expedition under Gen. John J. Pershing in pursuit of Villa, who then craftily drew Pershing some 350 miles (more than 560 km) into Mexican territory.
Fighting broke out between U.S. soldiers and Carranza’s troops in April, and war was averted only by Carranza’s and Wilson’s decision to appoint a joint high commission to negotiate. While these negotiations were going badly, in November 1916, the Carranza government informed the Germans that it could “to the extent of its powers in certain circumstances” assist German submarines operating in the Gulf of Mexico. Wilson withdrew all U.S. troops from Mexico early in February 1917, thus blunting Zimmermann’s offer, but he did not extend de jure recognition to Carranza until March 13.
Receipt from London of the text of the Zimmermann telegram on February 24, 1917, did not prompt Wilson’s decision for armed neutrality, but it did cause him to lose all faith in the German government. Moreover, publication of the telegram in the press on March 1 set off the first nationwide demand for war with Germany.
These events pushed the United States inexorably along the road to war. A small group of pacifist senators led by Wisconsin’s Robert La Follette prevented passage of the armed ship bill by filibuster, but Wilson used his authority as commander in chief on March 9, 1917, to arm merchant ships.
German submarines sank three U.S. merchant ships on March 18 with heavy loss of life. Supported by his cabinet, by most newspapers, and by a large segment of public opinion, Wilson made the decision for war on March 20, and the following day he called Congress to meet in special session on April 2. He delivered a ringing war message before that body on that date, saying that America would be privileged to give her blood and treasure to make the world safe for democracy. The Senate approved the war resolution on April 4, the House of Representatives on April 6. Later that day Wilson signed a resolution recognizing that a state of war existed between the United States and the German Empire.
This article was most recently revised and updated by Michael Ray.
The Zimmermann Telegram and American Entry into World War I
The fact that the telegram before him bore Arthur Zimmermann’s name made its contents that much harder for Walter Hines Page to believe.
Page was the American ambassador to Great Britain and on a cold London morning in late February 1917 the British foreign minister Arthur Balfour stood before him with what Page called a “bombshell.” Page had had high hopes for Zimmermann, recently named the new German foreign minister. Zimmermann was a member of the middle class, not the aristocracy that President Wilson’s administration so deeply mistrusted. He had thus far said all the right things and shown a receptiveness to Wilson’s cherished efforts to end the war through peace negotiations. The telegram Page stared at in numb disbelief proved beyond the shadow of a doubt that Zimmermann had been lying all along. Far from being a man the Americans could see as a partner for peace, he was instead the author of the most notorious message Page had ever seen.[1]
Balfour, knowing full well that the telegram might lead the Americans to enter the war on Britain and France’s side, had nevertheless hesitated to show it to Page. The Royal Navy admiral whose office, codenamed Room 40, had intercepted and decoded the telegram had also been wracked with doubt about what to do.
Although Admiral Sir William Hall knew exactly how important the telegram was, he had to find a way to show it to the Americans without revealing that his office had broken the German codes. Once the Germans learned that their codes and ciphers were no longer secure, they would stop using them and a veritable gold mine of information would stop flowing into Hall’s office. Only once he was convinced that he had found a way to protect his precious secret did he give the telegram to Balfour.
Page picked up the telegram one more time and read the words that he knew would force the United States into the war it had been trying desperately to avoid for three years:
We intend to begin on the first of February unrestricted submarine warfare STOP We shall endeavor in spite of this to keep the United States of America neutral STOP In the event of this not succeeding, we make Mexico a proposal of alliance on the following basis make war together, make peace together, generous financial support and an understanding on our part that Mexico is to reconquer lost territory in Texas, New Mexico, and Arizona STOP The settlement in detail is left to you STOP You will inform the President [of Mexico] of the above most secretly as soon as the outbreak of war with the United States of America is certain and add the suggestion that he should, on his own initiative, invite Japan to immediate adherence and at the same time mediate between Japan and ourselves STOP Please call the President’s attention to the fact that the ruthless employment of our submarines now offers the prospect of compelling England in a few months to make peace STOP Signed ZIMMERMANN[2]
It did not surprise Page that the Germans intended to resume sinking merchant ships.
He knew the Germans were contemplating such a move and that the United States Congress was even then debating a bill to arm merchant ships in response. The shocking parts of the telegram involved Mexico and Japan. Germany was effectively proposing an alliance to tear the United States apart in the event of American belligerence. The telegram was therefore an act of war. It was also so obviously in Britain’s interests to share it with him that Page knew his countrymen would suspect it was a forgery or a British trick.
Page knew, as did Wilson, that German agents were active in Mexico. They were trying to take advantage of the extremely poor state of Mexican-American relations that had existed since the start of the Mexican Revolution in 1911. Wilson had sent American forces to intervene in Mexico in an attempt to remove leaders he disliked. In his own words, he was trying to teach the Mexicans to elect good men. Most significantly, he had ordered American sailors and marines into Veracruz for six months in 1914, partly to prevent the German government from sending arms to the Mexican strongman Victoriano Huerta.
Violence in Veracruz eventually resulted in the deaths of nineteen Americans and 129 Mexicans. As part of the fallout, the Americans stopped sending arms to another aspirant to power, Mexican General Pancho Villa. Villa’s men responded by raiding New Mexico in March 1916, killing eighteen Americans. America’s ambassador in Berlin was convinced that the Germans were supporting Villa, hoping that if he became president he would grant Germany the right to build a port on Mexico’s Caribbean coastline.[3] An American expedition to find and punish Villa commanded by General John Pershing failed, leaving American relations with Mexico on a hair trigger.
American relations with Japan were also tense. Several western states had passed or were considering laws that banned Japanese men and women (including American citizens) from owning land. Word had also reached Washington of Japanese arms sales to Mexico as well as negotiations to build a Japanese naval base on Mexico’s Pacific coast. One of the sites mentioned was on the Baja peninsula where a Japanese cruiser suddenly appeared in April 1915.
The Americans saw these events as a violation of the Monroe Doctrine and a source of significant concern. The Wilson administration also knew that the Germans were trying to sway the Japanese with promises of territorial gains in China if they would declare war on Russia.
The Germans themselves were a headache for Wilson, who was trying as hard as he could to keep the United States neutral. The Germans were not making it easy for him. The sinking of the Lusitania in May 1915, which killed 128 Americans, had turned most Americans anti-German, if not yet pro-Allied. German spies were also active across the United States. They pulled off a spectacular incident of what we would today call state-sponsored terrorism when they blew up the Black Tom munitions depot in Jersey City, New Jersey, in April 1916. The blast killed seven people and was powerful enough to shatter windows as far away as Times Square. Suspicion initially fell on a workman who had lit fire pots to keep mosquitos away.
By the time investigators uncovered a German connection, the perpetrators had vanished.
Still, Wilson did not want to take the nation to war in large part because he believed that only as a neutral statesman could he bring the two sides to peace. He also knew that neutrality was popular with key constituencies of his Democratic Party, including the rural South and Midwest and the large Irish and German American communities whose sympathies were decidedly anti-English.
But even while Wilson was feeling pressure from the isolationists to stay out of the war, his biggest political rival, former President Theodore Roosevelt, was leading a vocal group that was urging Wilson to stand up to Germany. Already colored by their pro-British and pro-French sensibilities and furious at German atrocities in Belgium and on the high seas, Roosevelt and his allies urged America to get ready to fight a war to defend democracy and freedom in Europe. Roosevelt began giving speeches and writing regular newspaper articles lambasting Wilson as a coward who refused to stand up for American values and American rights.
The longer the war went on and the more Germany infringed on American interests, the harsher Roosevelt’s tone grew. He and his political allies had begun voluntary camps at Plattsburg, New York, to train young men in military service, although the real purpose of the movement was to shame Wilson into ordering the American Army to prepare for war.
Wilson’s extremely narrow victory in the 1916 election had given him four more years, but it had not solved his foreign policy dilemmas. Mexico remained an ulcer and Pershing’s inability to find Villa was a humiliation. Nor had the election silenced Roosevelt, who had supported Wilson’s opponent, Charles Evans Hughes. Roosevelt and his friend, Massachusetts Senator Henry Cabot Lodge, eyed a Republican victory in the 1918 midterm election, and Roosevelt had begun to hint that he might run for the presidency in 1920. Facing all of these problems and distant even from his own Cabinet, it was perhaps not surprising that Wilson seemed confused and unsure of how to deal with a world crisis that threatened to pull America into a war in Mexico or, worse still, into the trenches of the western front.
The telegram that Page transmitted to Washington was indeed a bombshell for Wilson. Although Wilson trusted Page’s assurances that the telegram was genuine, Wilson knew that he would need more than the ambassador’s word to convince the American people and the isolationists in Congress. He therefore sent an American intelligence expert to Room 40 to verify both the telegram and the cipher used to decode it. Admiral Hall had been reluctant, but eventually agreed, especially once he figured out how to protect his source. Hall’s men had intercepted a second version of the telegram, sent from the German embassy in Washington to the German mission in Mexico. The second telegram contained just enough changes in wording from the original that when the Americans published it, the Germans would likely conclude that someone in Mexico had leaked it. The existence of Room 40 could therefore remain Britain’s most important wartime secret.
The Zimmermann telegram appeared in American newspapers on March 1 and set off the reactions Wilson and Page had expected.
For many Americans, the potential combination of Mexico, Japan, and Germany represented nothing less than a nightmare. Newspapers across the country equated the telegram with a German declaration of war. Many of them also used racist imagery about the Japanese and Mexicans to depict them as servile agents of the smarter and more highly developed Germans. The fear was greatest in the West and Southwest, regions that had traditionally been isolationist. The Zimmermann telegram painted a future for people from Texas to California of invasion, the loss of their land, and conquest by the soldiers of Mexico and Japan. Supposition that the Germans might seize Canada from Britain in the event they won the war further stoked American fears. In a flash the war was no longer about events in Europe. It was now about threats to America itself.
Also predictably, many of Wilson’s political opponents refused to believe the telegram’s legitimacy. Republicans, Irish Americans, German Americans, and even some members of Wilson’s own party either thought the British were playing an elaborate ruse on the naïve president or refused to believe any diplomat could send anything as stupid as that telegram.
Wilson shared all the information he had with key isolationist senators who were even then preparing to filibuster the bill to arm merchant ships. Zimmermann gave Wilson one more gift by admitting to an amazed German media that he had indeed sent the telegram. Zimmermann saw no value in denying what the British and Americans could presumably prove. He also saw the value of having his offer of alliance out in the open, allowing him to pursue further diplomatic negotiations with the Japanese and Mexican governments. Japan’s ambassador to Germany, however, called the idea of an alliance “too ridiculous for words,” and, after giving it some thought, the Mexicans, too, backed away.[4] Zimmermann’s gamble had failed.
It remained to be seen, however, how Wilson would react. Roosevelt was so incensed he told a friend that if the President did not declare war he would “skin him alive.” He then petitioned Wilson for the right to raise and command his own division and lead it in combat in France.
Wilson, predictably, refused, leading Roosevelt to remark “I don’t understand. After all, I’m only asking to be allowed to die.”[5] An irate House of Representatives, which had been hotly debating the issue of arming merchant ships, reversed course and voted 500 to 13 in favor. It also added a provision to the bill authorizing the President to use the armed forces of the United States in any way he saw fit to protect American property and lives. Although it was unclear if the Senate would follow suit, it was perfectly clear that the mood in the country had changed dramatically. The isolationist and pro-German press, unable to defend Zimmermann or deny the telegram’s existence, simply went quiet or voiced support for the United States.
On March 20, with the American media still enraged, Wilson met with his Cabinet and found them for the first time unanimously in favor of war. Even the intensely pacifist Secretary of the Navy, Josephus Daniels, voiced his support for war. The next day Wilson told Congress to assemble on April 2, a full two weeks earlier than scheduled, to hear him address “grave matters of national policy.
” Zimmermann’s telegram had been the final straw. Wilson asked Congress for a declaration of war and took the first steps toward leading his nation into the most terrible war the world had ever known.
[1] Burton J. Hendrick, The Life and Letters of Walter Hines Page (Garden City, NY: Doubleday, 1925), 3:324.
[2] Details of the process of decoding the telegram, as well as much else, can be found in Barbara W. Tuchman, The Zimmermann Telegram (New York: Ballantine Books, 1958).
[3] Tuchman, The Zimmermann Telegram, 95.
[4] Hendrick, The Life and Letters of Walter Hines Page, 3:352.
[5] Edward J. Renehan Jr. The Lion’s Pride: Theodore Roosevelt and His Family in Peace and War (New York: Oxford University Press, 1998), 129. All five of Roosevelt’s children served in World War I. His son Quentin died when the Germans shot down his plane during the Second Battle of the Marne.
Michael S.
Neiberg is the author or editor of more than a dozen books, most of them dealing with World War I, its causes, and its global impacts. His most recent book is Dance of the Furies: Europe and the Outbreak of World War I (2011). Currently at work on a history of the liberation of Paris in 1944, he is a former Harry Frank Guggenheim fellow and is a professor of history at the United States Army War College.
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What if the Zimmermann telegram came to the address - Articles
The details were set out in a telegram sent by German Foreign Minister Arthur Zimmermann to the German embassy in Mexico. But the message fell into the wrong hands, which significantly affected the course of the war. What would happen if the telegram arrived at the address?
What happened?
Germany tried with all its might to keep the United States in a neutral status, counting on the fact that Washington would not support the Entente and would not enter the war.
The task was not an easy one. Firstly, many Americans went to the front as volunteers and, joining the ranks of the British army, became participants in the hostilities against Germany. Secondly, in the Atlantic, Germany and Great Britain waged unrestricted submarine warfare, in which United States citizens were often the victims. Of course, all German officers had an order not to touch American ships cruising the ocean.
The trouble for Germany, however, was the very intense contacts between the two English-speaking countries. And the British ships that were attacked by German submarines often ended up with citizens of the United States. The saddest example is the sinking of the Louisitania. It was a British passenger liner that was attacked on May 7, 1915 by a German U-20 commanded by Lieutenant Commander Walter Schwieger. One torpedo (according to Schwieger himself) sent the ship to the bottom. More than a thousand passengers died, including 120 US citizens, which, of course, caused a wave of protests and indignation from the US.
It is believed that the sinking of the Louisitania predetermined the entry of the United States into the war. It just happened two years later. The Zimmermann telegram played a much more important role, finally convincing Washington of the need to support the Entente.
Arthur Zimmerman. (wikipedia.org)
Let us return, however, to Zimmerman. The Foreign Minister of the German Empire was a staunch supporter of the idea that the entry of the United States into the war on the side of the Entente was inevitable and that this, in turn, would be a disaster for Germany. The diplomat came up with a rather cunning plan to create a counterbalance that would not allow the United States to send significant forces to Europe and withdraw its fleet to the Atlantic. The role of such a counterbalance was to be played by Mexico, to which Berlin was going to offer a secret alliance. The essence of the agreement is that in the event that the States join the Entente, Mexico will enter into a quadruple alliance and attack its northern neighbor.
At the same time, it was supposed to thoroughly warm up anti-American sentiments in Mexico.
Moreover, all sorts of promises were launched. In the event of victory, Germany promised Mexico Texas and Arizona, that is, those territories that used to belong to this country, and then became part of the United States. Zimmermann outlined this whole plan in his telegram, which he sent to Heinrich of Eckhard, the German ambassador to Mexico. Eckhard received the message, but along the way it was intercepted by British intelligence and deciphered in the famous Room 40 of the British Admiralty. Cryptographers solved the German cipher using the codes they already had. From that moment on, London had a deadly compromising evidence against Germany and a truly terrible trump card, which was skillfully played. The content of the telegram was handed over to the US authorities. 1 March 19On the 17th, its text was published in print. On April 6, Congress officially declared war on Germany.
Could it be otherwise?
It is unlikely.
The fact is that when sending the telegram, Zimmerman showed a naivete that was surprising for a man of his position and status. The fact is that Germany did not have direct telegraphic communication with the Western Hemisphere. The British cut off cables and destroyed German stations in neutral countries in the early stages of the war. In order to transmit diplomatic messages to its ambassadors in the countries of North and South America, Germany had to use the services of neutral countries. The Zimmermann telegram was transmitted to Mexico through two channels at once: through Sweden and the United States under the guise of a regular diplomatic message. Yes Yes. President Woodrow Wilson, who at the initial stages of the First World War still counted on maintaining warm relations between Washington and Berlin, allowed Germany to use American communication channels for its needs. Zimmerman apparently considered this channel reliable enough to use it to relay an extremely important message to Mexico.
Telegram. (pinterest.com)
What was the basis of the minister's confidence that the British did not check the diplomatic mail of neutral countries is not clear, but it was precisely in this confidence that Zimmerman's fatal mistake consisted. The telegram ended up with the British almost immediately after it was sent. Everything else was a matter of technique. The key problem was that London had to explain to Washington exactly how this message got to British intelligence. At the same time, two secrets could not be revealed: the first is that Great Britain checks the diplomatic mail of neutral countries, the second is that the British deciphered the German codes. Both of these issues have been successfully resolved. Moreover, in the course of the solution, the telegram was intercepted again. A certain British intelligence officer in Mexico (Agent X) intercepted a message on a telegraph line between Washington and Monterrey.
This text could easily be handed over to the United States without fear of grave diplomatic consequences.
In other words, Germany herself gave the Entente a deadly trump card against itself. If Zimmerman had found another way to transmit his telegram, then the United States might have remained a neutral power.
What would change?
If the United States had not entered the war in April 1917, then after the signing of the Treaty of Brest-Litovsk, Germany would have received a significant advantage in the conflict. The young RSFSR washed its hands, in fact capitulating to the enemy, which untied Berlin's hands. The German army could no longer think about the Eastern Front, where it was necessary to constantly pull the hopeless Austria-Hungary out of the swamp. All forces could be thrown to the west, where France still held out, but France was already bursting at the seams. Having broken through the front and broken the resistance of the eternal enemy, Germany would have achieved what she wanted: she would have been left face to face with her main enemy - Great Britain.
The loss of all positions and allies on the Continent would force London to seek peace. For Germany, this would mean actual victory in the war.
Caricature of the Zimmermann telegram. (pinterest.com)
However, in the spring and summer of 1917, the Entente received a serious boost of both resources and people. It all started with subsidies. The United States was already engaged in intensive trade with Great Britain, and here the States began to provide economic assistance to new allies on an unprecedented scale. And it would be fine if it was only about the supply. The US also gave France and Britain gigantic loans on fairly easy terms, at once increasing the external debt of the two countries to $24 million.
Another aid on a million scale was already of a military nature. The American fleet began active operations against Germany in the Atlantic, and soon the enemy was driven out of the ocean. In addition, more than a million soldiers went to Europe.
These divisions played an important role in the victory of the French troops in the famous Battle of the Marne, took part in the expulsion of the Austrians from Italy, and also carried out several of their own operations. Apogee - the participation of the Americans in the Hundred Days Offensive, which ended in a complete victory for the Allies and forced Germany to sue for peace. As a result, the United States became the main beneficiary of the First World War.
The infrastructure of the country practically did not suffer from bombing and other actions of the enemy. On the other hand, the timely support provided to the Entente made the United States one of the victorious countries. This was the first, but very important step towards future hegemony. Soon, the States will open their way to Asian and European markets, and the economy of post-war Germany will be fully pegged to the dollar.
The Zimmermann telegram became a ticket to a brighter future for the United States.
Another thing is that the States might not have pulled it out if the "ticketer" had found a more reliable way to send his famous telegram.
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Secret room 40 / Habr
In wartime, secure communication channels were used to exchange data.
And the interception of transmitted messages with their subsequent decryption played an important role in the confrontation between states. The ingenious cryptographers of Bletchley Park did a colossal job and significantly influenced the course of the Second World War. They gained worldwide fame, forever imprinting their names in the history of cryptography. But deciphering messages was also done during the First World War. In Britain, there was a decryption organization called Room 40 (Eng. Room 40), engaged in the interception and decryption of German messages.
Room 40 was also known as 40 S.B. (Old Building) and was a division of Britain's leading cryptographic authority during World War I, the British Admiralty. The organization was formed in October 1914, shortly after the start of the war. Room 40 got its name from the number of the room in the old Admiralty building, where it was located. For most of its existence, this organization was a bureau for the analysis and decryption of cryptograms.
About 15,000 German messages were deciphered by its employees.
Creation of Room 40
In 1911, the communications department of the Imperial Defense Committee decided that in the event of a war with Germany, German submarine communications should be immediately destroyed. On the morning of August 5, 1914, the cable ship Alert identified and cut off 5 German transatlantic cables that reached the English Channel. Shortly thereafter, 6 cables that ran between Britain and Germany were also cut off. As a result, the flow of messages transmitted by radio increased. Codes and ciphers were used to hide their contents. But neither the UK nor Germany had the appropriate organizations to decipher such messages. Messages that could be intercepted were sent to the intelligence department of the Admiralty, which, from 19For 13 years, Rear Admiral Henry Oliver led. But there were also no employees who could crack the code. Then Oliver turned to his friend, an engineer with experience in radio communications, Sir Alfred Ewing, and asked him to form a group to decipher the messages.
Sir James Alfred Ewing (1855-1935) was a Scottish physicist and engineer known for his work on the magnetic properties of metals. In 1879 he designed a seismograph close to the modern one. As a close friend of Charles Parsons, Ewing helped him develop the steam engine. At 189In the year 7, he took part in sea trials of the experimental vessel Turbinia, which developed the fastest speed at that time (35 knots).
Ewing diligently took up the study of cryptographic materials stored in the library of the British Museum. Then he took up the study of codes at the city's central post office, where copies of commercial code books were kept. In parallel with this, Ewing began to assemble a team, introducing four teachers from the Osborne and Dartmouth Naval Colleges to his activities. They were his friends, who spoke excellent German. Together they would gather in Ewing's office, studying incomprehensible strings of letters and numbers, having only the most general idea of how to start working on breaking ciphers.
By the middle of autumn 1914, the number of Ewing's group members had increased significantly, they no longer fit in his office. A more appropriately sized and technically equipped room was required. As a result, the formed team of codebreakers moved to the old building of the Admiralty and became known as Room 40. It had a good location - away from the busiest premises of the Admiralty and close enough to the operations department. Ewing became director of Room 40, with cryptographer Alistair Denniston appointed as his deputy.
Alistair Guthrie Denniston (1881-1961) - British cryptographer, the first director of the Government Communications Center intelligence service, who held this post in 1919-1942.
All the activities of Room 40 were kept strictly secret and only a very few officers in the Admiralty and on the ships of the English Navy knew of its existence. The ability to read radio reports from the German Navy gave officers more information about the operations and intentions of Admiral Scheer's fleet than was available in any other unit of the Royal Navy.
The intercepted and decoded text messages were sent to one of a small group of dedicated officers of the British Naval Headquarters Operations Directorate. Herbert Hope, who had previously worked on enemy shipping routes, was chosen to review all messages and interpret them in terms of information. Hope was located in a small room, where he tried to understand the meaning of the received messages and make useful observations. But he only gained full access to information over time, after a chance meeting with the First Lord of the Admiralty, Sir John Arbuthnot Fisher.
A significant disadvantage of Room 40's organization was that it could not act as an operational intelligence center. No messages processed by Room 40 could be sent out without Oliver's personal approval (with the exception of some approved by the First Lord or Lord of the Admiralty). The members of this organization understood that the information they decrypted was not used to the full extent due to extreme secrecy and prohibitions on sharing it with other intelligence departments.
As already mentioned, the transfer of information prepared in Room 40 and only to her well-understood information was entrusted to a small group of officers. But they did not possess either special knowledge or the appropriate skills to always correctly interpret the importance of decryptions and best manage their future fate.
In 1917, something changed - Room 40 stopped supplying the intelligence agency with raw information and began to transmit all the factual materials in the form of thoughtful assessments of the intentions and nature of the movements of the German ships.
SKM codebook holder
In 1914, Russia handed over to Great Britain the "Book of Imperial Navy Signals" (Signalbuch der Kaiserlich Marine, SKM), which was captured by Russian sailors on the German cruiser Magdeburg. The British copy of the book was presented personally to the First Lord of the Admiralty, Winston Leonard Churchill.
Cruiser Magdeburg
Obtaining the SKM was the first breakthrough for Room 40 employees.
In order to use the book, a current key was needed. A map of the Baltics, a ship's journal and military diaries were also restored.
Sheets from the SKM book (more can be seen here):
The SKM itself was incomplete, since messages were usually both encrypted and encoded. The German naval intelligence expert K. J. E. Rotter was tasked with using SKM to interpret the intercepted ciphers, most of which turned out to be meaningless when decrypted. The beginning of the solution to the problem was a series of messages transmitted from the German Norddeich transmitter. They were sequentially numbered and deciphered, proving to be reconnaissance reports on the whereabouts of allied ships. In fact, the cipher was broken twice, since a few days later it changed and the general procedure for interpreting messages was determined. Encryption was the usual table of replacing one letter with another in all messages.
The German Navy used SKM as a code during important operations.
Transmission between ships took place in the form of simple combinations of signal flags or lamp flashes. The SKM contained 34,000 instructions, each represented by a different group of three letters. The signals used four characters that regular Morse code does not have (which caused problems for decoders). But over time, Room 40 cryptographers learned to recognize and use a standardized way of recording signals. Ships were identified by a group of three letters, starting with the beta character. Messages not covered by a predetermined list could be written using a substitution table for individual letters.
The enormous size of the book was one of the reasons why it could not be easily modified. The code continued to be used until the summer of 1916. The actual substitution table that was used for encryption was generated by a mechanical device with thumbnails and compartments for letters. Key change orders were sent by radio. The confusion that occurred during the period of change led to the fact that the message was sent using a new cipher, and then repeated with the old one.
Key changes did not happen often, only 6 times from March until the end of 1915 years, but since 1916 they have become more frequent.
HVB codebook holder
An equally important code used by the German Navy was contained in the Handelsverkehrsbuch (HVB). Its copy came to the British after the successful capture of the German-Australian steamer Hobart in Australia on August 11, 1914. The German Navy used the code from the HVB cipher book to communicate with merchant ships, as well as within the High Seas Fleet.
Pages from the HVB book (see more here):
HVB was issued in 1913 to all warships with radio communication, naval command and coastal stations, and also distributed to the headquarters of eighteen German shipping companies for issuance to their own ships with radio communication. The code used 450,000 possible permutations of four letters. This gave an alternative representation of the same meaning, adding an additional ten letters, which were grouped for use in messages.
Most often, the code was used by patrol boats. It was also used for common tasks, such as entering and exiting the port. Submarines used a code with a more complex key.
In 1914, it became known from radio communications that German intelligence had learned of the passage of the HVB book to the British. Nevertheless, the code was replaced only in 1916 with the "Allgemeinefunkspruchbuch" (AFB) along with a new coding method. The British got a good idea of the new encryption method from test signals before it was introduced to real messages. This time even more organizations received the new code. Compared to its predecessor, AFB had more groups, but with only two letters. The first captured copy was taken from the downed Zeppelin, while others were recovered from sunken submarines.
Sheets from the AFB book (see more here):
Capture of the VB cipher book
In 1914, a copy of the third German cipher book called "Verkehrsbuch" (VB) came into Room 40.
She was restored after the sinking of the German destroyer S119 in the battle of Texel. The ship's commander threw overboard the secret documents in a lead box and it was believed that they were lost. But a month later, the box was pulled out and handed over to the staff of Room 40 for decryption. The box contained a copy of the Verkehrsbuch, which was used by the commander of the German fleet. There were 100,000 groups of 5 digits in the code, each with a special meaning. It was used to encrypt telegrams sent abroad to warships and naval attaches, embassies and consulates.
The code from VB gave access to communications between the naval attaches in Berlin, Madrid, Washington, Buenos Aires, Beijing and Constantinople.
Deciphered by the Room 40 team the log of the German submarine U20 (located in the National Archives in London)
Room 40 regularly intercepted messages and had very accurate information about the position of German ships.
Yet British ships received clear instructions to use their radio as infrequently as possible and on the lowest possible frequency.0536
Zimmermann Telegram
Room 40's most significant achievement in naval history was the deciphering of the Zimmermann Telegram. It was dated 19 January 1917 and was on its way from the German Foreign Office to Ambassador Heinrich von Eckardt in Mexico.
Under the guise of a diplomatic message, the telegram was transmitted by radio and telegraph through neutral states: Sweden and the USA. Germany had to use the telegraph channels of Britain and America. The Germans were forced to take this risk because they did not have direct telegraph access to the western hemisphere, as the British cut their transatlantic cables and destroyed their transmitting stations.
Zimmermann telegram
The text of the telegram stated that the German Foreign Minister Arthur Zimmermann had offered US territories (Arizona, New Mexico and Texas) to Mexico if it would take part in the war as a German ally.
The British government understood the value of this message. But it was necessary to solve two problems. First, to explain to the Americans how the Telegram was received, without disclosing the fact that British intelligence checks the diplomatic mail of neutral countries. Secondly, to give a public explanation of how the Telegram was decrypted, but in such a way that Germany would not suspect anything (that the codes were cracked).
The first problem was solved when the British received the ciphertext of the Telegram from the telegraph office in Mexico. The German ambassador transmitted the message from Washington to Mexico by commercial telegraph, so the Mexican telegraph office had a copy of the ciphertext. A British agent obtained this copy and handed it over to the Americans. The text was ciphered with the code 13040, a sample of which Britain got hold of back in Mesopotamia. The Germans encrypted their messages using the usual algorithm of the Ministry of Foreign Affairs and the key number 0075, which Room 40 experts had already partially cracked.
The algorithm included the replacement of words (encoding) as well as the replacement of letters (encryption). This is a common practice that was also used in Germany in another encryption method - the ADFGVX cipher.
According to the "official" version, the deciphered text of the Telegram was stolen by the British in Mexico and given to the Americans. On April 6, 1917, the United States declared war on Germany.
Code ADFGVX
The designer of the font is Colonel Fritz Nebel, a communications officer. The peculiarity of this cipher was that it was built on the combination of basic substitution and permutation operations. The substitution part of the cipher was based on the Polybius square.
The ciphertext contained only the letters "A", "D", "F", "G" and "X" (hence the name of the cipher). The choice of these letters was not accidental. If you represent them in the form of dots and dashes of Morse code, then they will differ significantly from each other.
In fact, it was the square of Polybius, in which the Latin alphabet fit in a certain order. From 1918, the letter "V" was added, complicating the cipher and increasing the encryption grid to 36 characters. This made it possible to include numbers from 0 to 9 in the plain text, in addition, the letters I and J began to be encrypted in different ways.
The cipher was based on 6 letters: "A", "D", "F", "G", "V" and "X". The cipher table for ADFGX was a 5 x 5 matrix, and for ADFGVX it was 6 x 6. Rows and columns were denoted by letters included in the cipher name. The arrangement of elements in the table was part of the key.
Cipher replacement for a letter of the source text consisted of letters denoting the row and column at the intersection of which it was located.
At the second stage, to perform the permutation, the resulting set of cipher replacements was entered line by line from top to bottom in the table. The table had a strictly defined number of columns, or it corresponded to the number of letters in the keyword.
The numbering of the columns was either previously agreed upon by the parties or corresponded to the position of the letters of the keyword in the alphabet. A new table was created with the keyword in the top row.
For example, consider the message in English: "attack will begin in 11 am". As a key, you can take the word "SECRET". But as a rule, longer keywords or phrases were used.
Table columns have been sorted alphabetically.
Then the letters were written out from the columns in accordance with their numbering, while the reading took place along the columns, and the letters were combined into five-letter groups. Thus, the final form of the ciphertext looked like this:
G X F G F F D F F A D D F A G F X D F A D X V F A F G F D D X X V F A X V D A G A X
The sequence of columns could be brought back to their original order using a keyword. Knowing the location of characters in the original table helped decipher the text.
Text of the telegram:
We intend to start a merciless submarine war on February 1st. No matter what, we will try to keep the US in a state of neutrality. However, in case of failure, we will offer Mexico: to wage war together and make peace together. For our part, we will provide financial assistance to Mexico and assure that, at the end of the war, she will receive back the territories of Texas, New Mexico and Arizona she has lost. We task you to work out the details of this agreement. You will alert President Carranza immediately and in top secret as soon as the declaration of war between us and the United States becomes a fait accompli. Add that the President of Mexico may, on his own initiative, inform the Japanese Ambassador that it would be very advantageous for Japan to immediately join our alliance. Draw the President's attention to the fact that we continue to make full use of our submarine forces, which will force England to sign peace in the coming months.
