How secure was the USSR´s control over Eastern Europe, 1948-c. 1989?: Hungary & Czechoslovakia

Hungary

 
 This was the last message sent by Hungarian people which rose up against Soviet rule in 1956 and demanded freedom in their country. At the end of the Second World War, Hungary was on the losing side. It had fought alongside of Nazi Germany, against the Soviet Union.
By the end of the war Hungary was being ruled by Soviet Power, it became a satellite state of the Soviet Union.

    Czechoslovakia

In July 1968 the Soviet leadership announced that it had evidence that West Germany was planning an Invasion of the Sudetenland and asked permission to send in the Red Army to protect Czechoslovakia. Dubcek refused. However, a month later troops from countries across the Warsaw Pact, led by the Soviets, invaded Czechoslovakia. Knowing they stood no chance the Czech government ordered its armed forces not to resist the invasion. The culture of reform known as the “Prague Spring” was crushed.

Both
How similar were events in Hungary in 1956 and in Czechoslovakia in 1968?