Question 1: Explain the purpose of a firewall in a computer network. How does it help improve security?

Answer: A firewall acts as a barrier between a trusted internal network and untrusted external networks, monitoring and controlling incoming and outgoing network traffic based on security rules. It helps prevent unauthorized access and cyber attacks.

Question 2: Describe what is meant by encryption in data security and give one example of when it might be used.

Answer: Encryption is the process of converting data into a coded form to prevent unauthorized access. It is used when sending sensitive information, such as personal details or passwords, over the internet.

Question 3: Identify two security threats that can affect a computer network and briefly explain how they can be mitigated.

Answer: Two threats are malware and phishing. Malware can be mitigated by using antivirus software, while phishing can be prevented through user awareness and email filtering.

Question 4: Complete the truth table for an AND gate with inputs A and B, and output C.

Answer: A | B | C 0 | 0 | 0 0 | 1 | 0 1 | 0 | 0 1 | 1 | 1

Question 5: Draw a logic circuit for a system that outputs true only when either input A or input B is true, but not both. Label the gates used.

Answer: A correct sketch will show an XOR gate with inputs A and B, and an output C. The XOR gate should be clearly labeled, and the input lines should connect to its inputs.

Question 6: Sketch a diagram of a simple network security system that includes a firewall, an intrusion detection system (IDS), and a secure Wi-Fi router. Use labels for each component.

Answer: A correct sketch will show a network with the internet connected to a Wi-Fi router, with a firewall and IDS placed between the internet and the internal network. Each component should be labeled clearly.

Question 7: What is the main difference between symmetric and asymmetric encryption? Provide one advantage of each.

Answer: Symmetric encryption uses the same key for both encryption and decryption, and it is faster. Its advantage is efficiency. Asymmetric encryption uses a pair of keys (public and private), and its advantage is secure key exchange.

Question 8: Describe a scenario where multi-factor authentication (MFA) improves network security.

Answer: MFA improves security by requiring users to provide two or more different types of verification, such as a password and a fingerprint, making it harder for unauthorized users to access the system.

Question 9: Identify and explain the role of an SSL certificate in online security.

Answer: An SSL certificate encrypts data exchanged between a user's browser and a website, ensuring that sensitive information like passwords or credit card details are secure from eavesdroppers.

Question 10: Complete the truth table for an OR gate with inputs A and B, and output C.

Answer: A | B | C 0 | 0 | 0 0 | 1 | 1 1 | 0 | 1 1 | 1 | 1

Question 11: Sketch a diagram of a network security architecture that includes a DMZ (Demilitarized Zone). Label all components clearly.

Answer: A correct sketch will show an internal network, the internet, and a DMZ zone in between. The diagram should include firewalls at the boundaries, with servers placed in the DMZ for public access, and internal servers protected behind the firewall.