Oberkommando der Wehrmacht in the context of "Cryptography"

The Battle of Britain (German: Luftschlacht um England, lit. 'air battle for England') was a military campaign of the Second World War, in which the Royal Air Force (RAF) and the Fleet Air Arm (FAA) of the Royal Navy defended the United Kingdom against large-scale attacks by Nazi Germany's air force, the Luftwaffe. It was the first major military campaign fought entirely by air forces. It takes its name from the speech given by Prime Minister Winston Churchill to the House of Commons on 18 June, 1940: "What General Weygand called the 'Battle of France' is over. I expect that the Battle of Britain is about to begin."

The Germans had rapidly overwhelmed France and the Low Countries in the Battle of France, leaving Britain to face the threat of invasion by sea. The German high command recognised the difficulties of a seaborne attack while the Royal Navy controlled the English Channel and the North Sea. The primary objective of the German forces was to compel Britain to agree to a negotiated peace settlement.

The German Instrument of Surrender was a legal document effecting the unconditional surrender of the remaining German armed forces to the Allies, ending World War II in Europe. It was signed at 22:43 CET on 8 May 1945 and took effect at 23:01 CET on the same day.

The day before, Germany had signed another surrender document with the Allies in Reims in France, but it was not recognized by the Soviet Union, which demanded among other things that the act of surrender should take place at the seat of government of Nazi Germany from where German aggression had been initiated. Therefore, another document needed to be signed. In addition, immediately after signing the first document, the German forces were ordered to cease fire in the west and continue fighting in the east. Germany under the Flensburg Government led by the head of state, Grand-Admiral Karl Dönitz, also accepted the Allied suggestion to sign a new document. The document was signed at the seat of the Soviet Military Administration in Germany (Karlshorst, Berlin) by representatives from the German Oberkommando der Wehrmacht (OKW), the Allied Expeditionary Force represented by the British, and the Supreme High Command of the Soviet Red Army, with further French and American representatives signing as witnesses. This time, Field-Marshal Wilhelm Keitel was the highest ranking representative of Germany at the signing ceremony. This surrender document also led to the de facto fall of Nazi Germany. As one result of the German downfall, the Allies had de facto occupied Germany since the German defeat – which was later confirmed via the Berlin Declaration by the four countries of Allies as the common representative of new Germany (France, USSR, UK and the US), on 5 June 1945.

The Waffen-SS (German: [ˈvafn̩ʔɛsˌʔɛs]; lit. 'Armed SS') was the combat branch of the Nazi Party's paramilitary Schutzstaffel (SS) organisation. Its formations included men from Nazi Germany, along with volunteers and conscripts from both German-occupied Europe and unoccupied lands. With the start of World War II, tactical control was exercised by the Oberkommando der Wehrmacht (OKW, "High Command of the Armed Forces"), with some units being subordinated to the Kommandostab Reichsführer-SS (lit. 'Command Staff Reich Leader-SS') directly under Reichsführer-SS Heinrich Himmler's control. It was disbanded in May 1945.

The Waffen-SS grew from three regiments to over 38 divisions during World War II. Combining combat and police functions, it served alongside the German Army (Heer), Ordnungspolizei (Order Police), and other security units. Originally, it was under the control of the SS Führungshauptamt (SS operational command office) beneath Himmler.

The Battle of Stalingrad (17 July 1942 – 2 February 1943) was a major battle on the Eastern Front of World War II, beginning when Nazi Germany and its Axis allies attacked and became locked in a protracted struggle with the Soviet Union for control over the Soviet city of Stalingrad (now known as Volgograd) in southern Russia. The battle was characterized by fierce close-quarters combat and direct assaults on civilians in aerial raids; the battle epitomized urban warfare, and it was the single largest and costliest urban battle in military history. It was the bloodiest and fiercest battle of the entirety of World War II—and arguably in all of human history—as both sides suffered tremendous casualties amidst ferocious fighting in and around the city. The battle is commonly regarded as the turning point in the European theatre of World War II, as Germany's Oberkommando der Wehrmacht was forced to withdraw a considerable amount of military forces from other regions to replace losses on the Eastern Front. By the time the hostilities ended, the German 6th Army and 4th Panzer Army had been destroyed and Army Group B was routed. The Soviets' victory at Stalingrad shifted the Eastern Front's balance of power in their favour, while also boosting the morale of the Red Army.

Both sides placed great strategic importance on Stalingrad, for it was one of the largest industrial centres of the Soviet Union and an important transport hub on the Volga River: controlling Stalingrad meant gaining access to the oil fields of the Caucasus and having supreme authority over the Volga River. The city also held significant symbolic importance because it bore the name of Joseph Stalin, the leader of the Soviet Union. As the conflict progressed, Germany's fuel supplies dwindled and thus drove it to focus on moving deeper into Soviet territory and taking the country's oil fields at any cost. The German military first clashed with the Red Army's Stalingrad Front on the distant approaches to Stalingrad on 17 July. On 23 August, the 6th Army and elements of the 4th Panzer Army launched their offensive with support from intensive bombing raids by the Luftwaffe, which reduced much of the city to rubble. The battle soon degenerated into house-to-house fighting, which escalated drastically as both sides continued pouring reinforcements into the city. By mid-November, the Germans, at great cost, had pushed the Soviet defenders back into narrow zones along the Volga's west bank. However, winter set in and conditions became particularly brutal, with temperatures often dropping tens of degrees below freezing. In addition to fierce urban combat, brutal trench warfare was prevalent at Stalingrad.

Wilhelm Bodewin Johann Gustav Keitel (German pronunciation: [ˈvɪlhɛlm ˈkaɪtl̩]; 22 September 1882 – 16 October 1946) was a German field marshal who held office as chief of the Oberkommando der Wehrmacht (OKW), the high command of Nazi Germany's armed forces, during World War II. He signed a number of criminal orders and directives that led to numerous war crimes.

Keitel's rise to the Wehrmacht high command began with his appointment as the head of the Armed Forces Office at the Reich Ministry of War in 1935. Having taken command of the Wehrmacht in 1938, Adolf Hitler replaced the ministry with the OKW and Keitel became its chief. He was reviled among his military colleagues as Hitler's habitual "yes-man".

The Oberkommando des Heeres (lit. 'Upper Command of the Army'; abbreviated OKH) was the high command of the Army of Nazi Germany. It was founded in 1935 as part of Adolf Hitler's rearmament of Germany. OKH was de facto the most important unit within the German war planning until the defeat at Moscow in December 1941.

During World War II, OKH had the responsibility of strategic planning of Armies and Army Groups. The General Staff of the OKH managed operational matters. Each German Army also had an Army High Command (Armeeoberkommando or AOK). The Armed Forces High Command (Oberkommando der Wehrmacht) then took over this function for theatres other than the Eastern front.

The Armistice of 22 June 1940, sometimes referred to as the Second Armistice at Compiègne, was an agreement signed at 18:36 on 22 June 1940 near Compiègne, France by officials of Nazi Germany and the French Third Republic. It became effective at midnight on 25 June. Signatories for Germany included Colonel General Wilhelm Keitel, head of the German armed forces (OKW), while those on the French side held lower ranks, led by General Charles Huntziger.

Following the decisive German victory in the Battle of France, the armistice established a German occupation zone in Northern and Western France that encompassed about three-fifths of France's European territory, including all English Channel and Atlantic Ocean ports. The remainder of the country was to be left unoccupied, although the new regime that replaced the Third Republic was mutually recognised as the legitimate government of all of Metropolitan France except Alsace–Lorraine.

Oberbefehlshaber West (German: initials OB West) (German: "Commander-in-Chief [in the] West") was the overall commander of the Westheer, the German armed forces on the Western Front during World War II. It was directly subordinate to the Oberkommando der Wehrmacht (the German armed forces High Command). The area under the command of the OB West varied as the war progressed. At its furthest extent, it reached the French Atlantic coast. By the end of World War II in Europe, it was reduced to commanding troops in Bavaria.