Secure SSH Login on Linux with SSH keys

This is a brief summary of the steps required to create a secure SSH login using public-private keys on Linux server.
A reference to the full guide can be found here:
DigitalOcean SSH Setup Guide

Requirements:

• Linux server
• A Linux based client such as MacOS

Configuring the client

1- Generate public/private keys on the client:

ssh-keygen -t rsa

You can press enter for all prompts provided by the setup wizard.

2- Copy the private key to your server:

ssh-copy-id user@server-ip-address

Notes:
In this step you need to specify the user which this key will be associated with.
You'll be prompted to enter the login password for this user as well.

3- You are ready to use the key to login:

ssh user@server

Disabling Password Authentication

1- Login to your server:

ssh user@server

2- Edit SSH Daemon's configuration file:

sudo nano /etc/ssh/sshd_config

3- Search for the line that starts with PasswordAuthentication and uncomment it if it is commented and change it to:

PasswordAuthentication no

4- Restart SSH service to apply changes:

sudo service ssh restart