Two ways to use ssh -- Which one is more secure?

Question

Quoted from wikipedia:

There are several ways to use SSH:

• one is to use automatically generated public-private key pairs to simply encrypt a network connection, and then use password authentication to log on.

• Another is to use a manually generated public-private key pair to perform the authentication, allowing users or programs to log in without having to specify a password.

I know and have experience in both environments and I understand the outcome of each; But I fail to understand how is the above set up? and is there a difference from security point of view? I am not able to find a good resource on the web.

Answer 1

Once a ssh server is installed it will usually accept password and public-key authentication. Allowing only public-key authentication is more secure than allowing password authentication (see Ubuntu documentation link below for an explanation). Password authentication can be disabled in the server's config file.

To make public-key authentication work for you:

1. Create a public/private RSA key pair on your client computer
2. Transfer your public key to all servers you wish to log in to.

Here are some resources for completing those steps on Ubuntu. You haven't told us which systems and programs you are using. The details will vary with system.

How can I set up password-less SSH login?

Ubuntu Documentation - SSH OpenSSH Keys