Basic Public key question I'm studying public key cryptography, but still, there's something that I'm not able to understand. I know that, in order to communicate with the server the client must use the public key of the server, but what happens when the server needs to send a message to the client?

It can't use its private key since anyone would be able to decrypt the message, so my question is: ​ Does the client have a public key?
... what happens when the server needs to send a message to the client?


The server uses the symmetric key that the client sent to the  server.


  Does the client have a public key?" 


Sometimes.