Elyesa Bazna (ˈeljesa ˈbazna), sometimes known as Ilyaz and Iliaz Bazna (iliaz bazna; 28 July 1904 – 21 December 1970), was a secret agent for Nazi Germany during World War II, operating under the code name Cicero.
In 1943, Bazna was hired as a valet by Hughe Knatchbull-Hugessen, the British ambassador in Ankara, Turkey. He photographed British documents in Knatchbull-Hugessen's possession, and sold them to the Germans through their attaché Ludwig Carl Moyzisch in what became known as the Cicero affair.
As Cicero, Bazna passed on important information about many of the Allied leaders' conferences, including the Moscow, Tehran and Cairo Conferences. The details for the Tehran Conference were important for Operation Long Jump, the unsuccessful plot to kill Franklin D. Roosevelt, Joseph Stalin, and Winston Churchill.
Bazna had also conveyed a document that carried the highest security restriction (BIGOT list) about Operation Overlord (the code name for the Invasion of Normandy in June 1944). It included intelligence that the British ambassador was to request the use of Turkish air bases "to maintain a threat to the Germans from the eastern Mediterranean until Overlord is launched." The information about the Normandy Invasion was not known by the Germans until after the war. Had it been provided in time, Operation Overlord (the preparations for D-Day) would have been compromised. He also provided intelligence that might have made the Germans believe that there was no danger of attack in the Balkans.
The information that he leaked is believed to have been among the more damaging disclosures made by an agent during WWII. The German Foreign Office questioned the reliability of the intelligence provided by Cicero due to the large quantity of transmitted documents, which meant that apparently little, if any, of it was acted upon. It seems likely that he had received some intelligence training from the Italian secret intelligence service, SIM.