It is important in this process to create a superb passphrase, and there’s no excuse not to. The user's account name is 'accountname'. In the examples below, the remote machine's name is called 'remotehost'. One can repeat the process for different sets of machines, for example, a key pair for different levels of security for different departments home and work and so on. The public key can then be distributed to any number of machines. This document will show you how to create an SSH key pair. SSH keys nearly eliminates the risk posed by brute-force password attacks by reducing the chances of an attacker guessing any proper credentials.

SSH keys allow authentication without sending a password over the network making it impossible for anyone eavesdropping on the network to see or crack your password. There are numerous methods for dealing with SSH keys to make the use of SSH easier and more secure.

How does one Setup SSH keys on a Mac to make for easier and more secure SSH sessions? Overview

Ssh for mac os