18.1.2. Private Key or Symmetric Key Encryption

Try these first

1. 1.

   What is the primary function of symmetric key encryption?

   Hint

   Think about the type of key used.

2. 2.

   Define ciphertext.

   Hint

   This is what happens to plaintext after encryption.

3. 3.

   What is symmetric key encryption?

   • A method using different keys for encryption and decryption
   • A method using the same key for both encryption and decryption
   • A method that doesn't use keys

   Hint

   Focus on the key's role in both processes.

4. 4.

   True or False: The Diffie-Hellman protocol allows two parties to agree on a key over a public channel securely.

   • True
   • False

   Hint

   Is it possible to securely share a key in public?

5. 5.

   Assuming Sita uses a 128-bit key for symmetric encryption, how many possible keys are available? Discuss the implications of this number in terms of brute-force attacks.

   Hint

   Think about the significance of key size in cryptography.

6. 6.

   Analyze a situation where an attacker could successfully execute a man-in-the-middle attack on the key agreement process. What measures could Sita and Ram take to prevent this?

   Hint

   Consider real-world examples of identity verification in communication.