18.3.2. Asymmetric Tasks

Try these first

1. 1.

   What is symmetric key encryption?

   Hint

   Think about what makes it secure.

2. 2.

   Name one challenge of establishing a common key over a public channel.

   Hint

   Consider who might be listening.

3. 3.

   What is the role of the common key in symmetric encryption?

   • To encrypt messages only
   • To decrypt messages only
   • To both encrypt and decrypt messages

   Hint

   What happens to a message before it reaches the recipient?

4. 4.

   True or False: The Diffie-Hellman protocol requires both parties to establish a secure channel before agreeing on a key.

   • True
   • False

   Hint

   What is unique about this protocol?

5. 5.

   Design your own key exchange protocol similar to Diffie-Hellman, detailing how it could securely share information over a public channel.

   Hint

   Think about the example of mixing colors and how each participant can add their secret.

6. 6.

   Critically evaluate the security risks if a common key is not established in secure communications.

   Hint

   Imagine if anyone could read emails between Sita and Ram!