**Chapter-1**

1. What is the OSI security architecture?

2. List and briefly define the three key objectives of computer security.

3. List and briefly define categories of passive and active security attacks.

4. List and briefly define categories of security services.

5. List and briefly define categories of security mechanisms.

6. List and briefly define the fundamental security design principles.

7. Explain the difference between an attack surface and an attack tree.

**Chapter-2**

1. What does it mean to say that *b *is a divisor of *a*?

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

3. What is the difference between modular arithmetic and ordinary arithmetic?

4. What is a prime number?

5. What is Euler’s totient function?

6. 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?

7. What is a primitive root of a number?

8. What is the difference between an index and a discrete logarithm?

**Chapter- 3**

1. Describe the main requirements for the secure use of symmetric encryption.

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

3. Differentiate between secret-key encryption and public-key encryption.

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

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

6. List and briefly define types of cryptanalytic attacks based on what is known to the attacker.

7. What is the difference between an unconditionally secure cipher and a computationally secure cipher?

8. Why is the Caesar cipher substitution technique vulnerable to a brute-force cryptanalysis?

9. How much key space is available when a monoalphabetic substitution cipher is used to replace plaintext with ciphertext?

10. What is the drawback of a Playfair cipher?

11. What is the difference between a monoalphabetic cipher and a polyalphabetic cipher?

12. What are two problems with the one-time pad?

13. What is a transposition cipher?

14. What are the drawbacks of Steganography?

total 6 pages