1 What are the essential ingredients of a symmetric cipher? 2 What are the two basic functions used in encryption algorithms? 3 How many keys are required for two people to communicate via a cipher? 4...

1
What are the essential ingredients of a symmetric cipher?

2
What are the two basic functions used in encryption algorithms?

3
How many keys are required for two people to communicate via a cipher?

4
What is the difference between a block cipher and a stream cipher?

5
What are the two general approaches to attacking a cipher?