Algorithm of a Feistel cipher

1 Explain the avalanche effect.

2 Briefly define a group.

3 Briefly define a ring.

4 Briefly define a field.

5 What does it mean to say that b is a divisor of a?

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

2 Why is it not practical to use an arbitrary reversible substitution cipher of the kind?

3 What is a product cipher?

4 What is the difference between diffusion and confusion?

5 Which parameters and design choices determine the actual algorithm of a Feistel cipher?

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