18.1.1. Introduction to Secure Communication

Try these first

1. 1.

   What is the purpose of encryption?

   Hint

   Think about what needs to be kept secret.

2. 2.

   What is ciphertext?

   Hint

   Consider what happens to a message when it's encrypted.

3. 3.

   What does encryption do to a message?

   • Makes it readable
   • Makes it unreadable
   • None of the above

   Hint

   Consider the goal of encryption.

4. 4.

   True or False: The same key is used for both encryption and decryption in symmetric encryption.

   • True
   • False

   Hint

   Think about the symmetry in the name.

5. 5.

   Investigate a scenario where an attacker has intercepted a key exchange using Diffie-Hellman. What consequences arise if the discrete logarithm problem is easily solvable?

   Hint

   Consider the implications of breaking the underlying math principle.

6. 6.

   Explain how symmetric encryption can be undermined in the case of key exposure. Provide an analysis of possible breaches.

   Hint

   Think about how a lost key might affect the security of a lock.