The Nazis Got Wind of the Big Three’s First Conference
There was good cause for worry about the security of the planned Tehran Conference. The Germans’ intelligence presence in Iran had mushroomed after the country was occupied by the British and Soviets. It was reasonable to expect that they would do what they could to derail the conference if they got wind of it. The Germans got wind of it after their military intelligence, the Abwehr, cracked a US Navy code, and discovered that a major WWII conference was to be held in Tehran, tentatively scheduled for October, 1943.
The information was passed on to Hitler, along with recommendations to disrupt the planned Allied meeting with a commando attack. The result was Operation Long Jump, which aimed to assassinate the Big Three Allied leaders in order to definitively derail the Tehran Conference. Operational control was passed to SS general Ernst Kaltenbrunner, chief of the Reichssicherheitshauptamt (RSHA – the German acronyms of the Reich Main Security Office). The RSHA was the Nazis’ intelligence arm, which combined the SS intelligence service and the interior ministry’s security police.