3. You exchanged encrypted messages with your instructor and another student. However, you first had to retrieve their public key from the key server before you could send an encrypted message. Answer the following:

Why were you able to digitally sign a message and send it to your instructor before downloading their public key?

Why was it necessary to have access to their public key prior to sending them an encrypted message?

4. The digital signature layer used a hash function and encryption function to digitally sign the message. a. Explain how the hash and encryption functions were used together to digitally sign the message. b. Did the digital signature use symmetric or asymmetric encryption? i. If the digital signature used asymmetric encryption, what key was used? Be specific. Note if it was the public or private key of the sender or recipient.