Lesson Plan

• Describe the process of encryption and decryption and differentiate between plaintext and ciphertext.
• Compare symmetric and asymmetric encryption, citing key characteristics and typical algorithms.
• Explain how hybrid encryption combines symmetric and asymmetric techniques in protocols such as TLS.
• Identify the main stages of the TLS handshake and the role of digital certificates in establishing trust.
• Perform basic RSA key‑generation calculations and apply RSA encryption/decryption formulas.

• Projector and screen
• Whiteboard and markers
• Student worksheets with encryption comparison tables
• Laptops or tablets with an online cipher tool/IDE
• Printed diagram of an X.509 digital certificate
• RSA calculation handout
• Sample TLS handshake diagram

Begin with a quick poll: how many students have noticed the padlock icon in a web browser? Review that they already understand passwords and basic data privacy. Explain that today they will uncover how computers scramble data using encryption and how trust is established through digital certificates. Success will be shown by correctly explaining the TLS handshake and completing a simple RSA calculation.

1. Do‑now (5') – Students answer the poll and write a brief definition of encryption on sticky notes.
2. Mini‑lecture (10') – Present the concepts of encryption, symmetric vs asymmetric, using slides and examples.
3. Guided activity (12') – Complete a handout comparing AES and RSA characteristics.
4. Live demonstration (8') – Walk through RSA key generation and encryption using a calculator or online tool.
5. Group task (15') – Simulate hybrid encryption: generate a random session key, encrypt it with RSA, then encrypt a short message with AES.
6. TLS handshake walkthrough (10') – Step‑by‑step diagram discussion, highlighting the role of digital certificates.
7. Check for understanding (5') – Quick quiz or Kahoot covering the objectives.
8. Recap & homework assignment (5') – Summarise key points and hand out practice questions.

Recap that encryption protects data, hybrid methods balance speed and security, and digital certificates create trust in online communications. Ask students to write one key takeaway on an index card as an exit ticket. For homework, complete the RSA calculation and TLS verification questions from the worksheet.