Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Computer Science
Lesson Topic: Understand the need for and purpose of encryption when transmitting data
Learning Objective/s:
  • Describe why encryption is essential for data transmitted over networks.
  • Explain the roles of plaintext, ciphertext, keys, and the encryption/decryption process.
  • Compare symmetric and asymmetric encryption in terms of key usage, advantages, and disadvantages.
  • Identify real‑world applications such as HTTPS, VPNs, and secure email.
  • Discuss key management challenges including generation, distribution, storage, and revocation.
Materials Needed:
  • Projector or interactive whiteboard
  • Slide deck covering concepts and examples
  • Handout with a summary table of encryption types
  • Worksheet with sample plaintext/ciphertext activities
  • Laptops/tablets with internet access for a HTTPS demo
  • Whiteboard and markers
 Introduction:

Start with a quick poll: Who has recently used online banking or visited a website with “https”? Briefly discuss how data travels over the internet and why it can be intercepted. State that by the end of the lesson students will be able to explain how encryption protects that data.
Lesson Structure:
  1. Do‑now (5'): Students write one example of personal data they think is risky to send online and share.
  2. Mini‑lecture (10'): Explain why encryption is needed – confidentiality, integrity, authentication, non‑repudiation.
  3. Concept walkthrough (10'): Define plaintext, ciphertext, key; demonstrate a simple Caesar cipher.
  4. Compare encryption types (8'): Review symmetric vs. asymmetric tables, discuss speed vs. security trade‑offs.
  5. Real‑world examples (7'): Show HTTPS handshake demo, discuss VPN and secure email use cases.
  6. Key management discussion (5'): Highlight generation, distribution, storage, revocation.
  7. Check for understanding (5'): Exit ticket – one sentence explaining why encryption matters in data transmission.
Conclusion:

Recap the core ideas: encryption transforms data to keep it confidential, ensures integrity, and supports authentication. Collect exit tickets and remind students to submit them before leaving. For homework, ask them to research one encryption algorithm (e.g., AES or RSA) and write a short paragraph describing its purpose and typical use.