16.4.2. Encryption Process

Try these first

1. 1.

   What are the two keys used in public key cryptography?

   Hint

   Think about the terms used for keys.

2. 2.

   What does ciphertext refer to?

   Hint

   Consider what happens to a message during encryption.

3. 3.

   What is the main advantage of public key cryptography over symmetric key systems?

   • A) It requires both parties to share a secret key.
   • B) It allows secure communication without sharing a secret key beforehand.
   • C) It is faster than symmetric key cryptography.

   Hint

   Consider the role of public and private keys.

4. 4.

   True or False: ElGamal encryption relies on the difficulty of factorizing large integers.

   Hint

   Think about the mathematical foundation of ElGamal.

5. 5.

   Using RSA, describe how you would encrypt a message if your public key is (N=15, e=7) and the message is 3. What would be the ciphertext?

   Hint

   Use exponentiation and modulo operations to find the answer.

6. 6.

   Discuss the implications of a scenario where the private key of an ElGamal encryption system is compromised. What would be the worst-case scenario?

   Hint

   Think about the effects on confidentiality and sender authenticity.