To assign while creating a new cloud server.RSA key pair generated through PuTTYgen is used in two various ways defined as below: Copy that entire text to your clipboard by pressing ctrl+c as you will require the key to paste on your clipboard in the public key tool of control panel or directly on the cloud server. You will see the text starting with ssh-RSA in the Public key for pasting into OpenSSH authorized_keys file field which is located at the top of the window.Click on the “Save Public Key” and “Save Private Key” buttons to save your public and private keys.Now you will need to add a unique key passphrase in the Key passphrase and Confirm passphrase field.Clicking on it will lead to generating the keys for you. You will find a “Generate” button in that dialog.You will see the PuTTY key generator dialog box on your screen.For the same, go to Windows -> Start Menu -> All Programs -> PuTTY -> PuTTYgen. Once you install the PuTTY on your machine, you can easily run PuTTYgen.Below is the complete guidance about how to generate RSA key in Windows operating system: PuTTYgen is used to generate public or private key pair for creating SSH keys. 2.3.2 Various Command Line Options of PuTTY in Linux.2.3.1 Generate Key Pair for Authentication in Linux.