SSH stands for Secure Shell and is an authentication method used by most Linux machines.

The traditional way of logging in with SSH is by username and password, however SSH keys are much more secure.

Rather than specifying a password, you place your public key on the machine you are trying to access and authenticate with the remote machine using your private key.

Generate a Key Pair

To generate the above keypair, you can run the command: ssh-keygen

You can specify somewhere to store it or just press ENTER to use the default location it shows:

You can also specify a passphrase that must be used when you authenticate with your private key, or just ENTER again to skip:

You should then find 2 files inside the .ssh directory within your home directory (providing that you didn’t rename/move it):

• id_rsa is your private key - this should NEVER be shared
• id_rsa.pub is your public key - this can be placed on any machine you wish to connect to

Using Your Key Pair

You can manually place your public key e.g. id_rsa.pub on the remote machine by copying and pasting the contents into the .ssh/authorized_keys file in your home directory on the remote machine.

You may need to create the file if it doesn’t exist already.

Alternatively, you can use the ssh-copy-id -i ~/.ssh/id_rsa <ip address> command to automatically copy the public key to the remote machine.

Replace <ip address> with the IP address of the remote machine .