The Allies were able to gain a foothold in Normandy on D-Day through extensive use of information operations including military deception, operational security, and command and control warfare. They manipulated German intelligence through a double agent network that fed misinformation about the timing and location of the invasion. Extensive security measures concealed real plans. Deception operations like Fortitude convinced Germany that Calais was the target. Coordinated sabotage by French resistance disrupted German communications just before D-Day. These information operations surprised the Germans and allowed the Allies to establish a beachhead with fewer casualties than expected, setting the stage for opening a Western Front.