The strategy involved in the invasion of normandy on d-day

The Allies created a fictitious 4th army, code named skye. To sum it up, they had double agents working with Germany that began spreading this rumor along with images of the Allied falsified army prepared for invasion. Germans thought they intercepted this message so they waited for this army to arrive from the British Isles as battles went on in France. All of which lead to a victory for the Allies.