List the steps required for validating a certificate in PKI infrastructure. Why is it important for a private key to be protected?

Each question will be graded based on the quality of explanation in response to the
question.
The grading criteria is as follows:
• Relevance: it provides direct answers to the question (30%).
• Understanding: The student clearly demonstrates proper knowledge of the
materials and techniques (30%).
• Length: The answer meets the word count requirement (10%).
• Clear Style: Sentences are easy to understand and straight forward (10%).
• Use of own words: The answer is written in student’s own words and provides
correct sources (10%).
• Language: Avoidance of inappropriate languages (10%).

(10 points) (minimum 150 words)
1. List the steps required for validating a certificate in PKI infrastructure. Why is it
important for a private key to be protected?
(10 points) (minimum 150 words total)
2.1. Describe the security problems that may result from the use of USB flash
memory-based storage devices.
2.2. Define shoulder surfing attack and explain how you would effectively protect
yourself from such attack.
(15 points) (minimum 200 words)
3. What’s the difference between LAN and WAN? Describe the process of local packet
delivery in LAN. What is MAC address? How are MAC addresses assigned?
(15 points) (minimum 200 words)
4. What’s the main difference between UDP and TCP protocol? Describe them in terms
of their transmission speed, reliability and connection overhead. Also, list at least two
examples of their use-cases in the application domain.