In this tutorial we are going to see how to configure SSH key to PUTTY for direct login to cloud server using public key authentication instead of password.
Why should we do this?
SSH key provide more secure way of logging instead of password. While a password can eventually be cracked with a brute-force attack, SSH keys are nearly impossible to decipher by brute force alone. With public key authentication, every computer has (i) a public and (ii) a private “key” (two mathematically-linked algorithms that are effectively impossible to crack).
You can use the same SSH key for multiple cloud server as they all saved with you public key and your private key file is saved on your computer. You can disable normal username/password login procedure, which mean only people with private/public key can access the server, which will be more secure.
keviveks Blog 