Euler’s totient function

1 What is a prime number?

2 What is the meaning of the expression a divides b?

3 What is Euler’s totient function?

4 The Miller-Rabin test can determine if a number is not prime but cannot determine if a number is prime. How can such an algorithm be used to test for primality?

5 What is a primitive root of a number?

1 Why do some block cipher modes of operation only use encryption while others use both encryption and decryption?

2 What is the difference between statistical randomness and unpredictability?

3 List important design considerations for a stream cipher.

4 Why is it not desirable to reuse a stream cipher key?

5 What primitive operations are used in RC4?