What role does propaganda play in totaltarian regimes?

The rise of totalitarianism, to some historians, was a logical process, but still has caused much discussion over the years. Many prominent dictators had fulfilled the yardsticks of totalitarianism to a large extent and one of these yardsticks is the use of Propaganda. As for many of the yardsticks, there are a number of pertinent reasons that make propaganda such a prominent feature of totalitarian regimes.