16.3.1. Keys in Public Key Cryptosystem

Try these first

1. 1.

   What is the primary purpose of public key cryptography?

   Hint

   Think about how messages can be sent over insecure channels.

2. 2.

   Define the term 'public key.'

   Hint

   Consider its role in the encryption process.

3. 3.

   What is a public key?

   • A key that is kept secret
   • A key that is shared publicly
   • A key used for decryption

   Hint

   Think about who can use it to encrypt messages.

4. 4.

   True or False: The Diffie-Hellman protocol requires both parties to be online simultaneously.

   • True
   • False

   Hint

   How do they achieve key agreement?

5. 5.

   How would you apply the Diffie-Hellman protocol in a scenario where two parties wish to establish a secret communication? Provide a step-by-step method.

   Hint

   Consider how public values are created and shared.

6. 6.

   Given a prime number and a corresponding public key in RSA, explain how an attacker could theoretically break the encryption. Discuss the feasibility of this approach.

   Hint

   Think about the reliance on large primes and their properties.