I'm going to be connecting to one of my servers from my boss' computer (Win 10) using PuTTY. In order to do so, I'll be using my private key. Is there anything I should do before/after to prevent my key from being stolen?

My plan was: 


Install PuTTY
add priv_key file to it
connect
… 
Uninstall PuTTY
remove priv_key


A more secure alternative is to create a new keypair that you use for this purpose. 


Create the keypair on your boss' computer.
Transfer the public key to your own computer. 
Connect to the server and add the public key.


Now your boss' computer can connect to the server. When this is done, you can remove the key on the server. This way, your own key does not leave your computer and your boss' key is only valid a short while.
