PuTTYgen is a free, open-source PC application for establishing a secure connection to another computer running the PuTTY program. You can use this generator from either Windows or Linux computers – however, you will have more better access to it on a Windows computer.
To start, go to ‘PuTTY’ and open ‘PuTTY Generator’
To create a new key pair, click on the Generate button near the bottom and move your mouse around within this window. Keep going until you see a green progress bar at the very bottom that fills up.
After the process is finished, your public key will be shown in the window.
You can save public or private key for your server