Creating SSH keys

[sio-gcastillo@workstation ~]$ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/sio-gcastillo/.ssh/id_rsa): 
Created directory '/home/sio-gcastillo/.ssh'.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/sio-gcastillo/.ssh/id_rsa.
Your public key has been saved in /home/sio-gcastillo/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:ufN+gZXovvcnNBFhgwNthreTXISWnCoKLfaqGauz6Pw sio-gcastillo@workstation
The key's randomart image is:
+---[RSA 3072]----+
|          .= *=. |
|          . &.o. |
|     .     O * . |
|    + . ..o B .  |
|   . + .So o . . |
|      o  .o . o  |
|  .  .  o.   o . |
|+  +.    o. o . .|
|=*=E     .++ ..o |
+----[SHA256]-----+

It is highly recommended to put a passphrase on your key.

You now have a public key(id_rsa.pub) & a private key(id_rsa). The public key can be added to a remote system to allow you to access it via ssh in a secure manner. Do NOT share the private key.

You can view the contents of your public key

[sio-gcastillo@gworkstation ~]$ cat ~/.ssh/id_rsa.pub 
ssh-rsa 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 sio-gcastillo@workstation

To use this key we’ll want to get it added to the target system. There is a script that comes with many ssh clients to help with this, ssh-copy-id :

$ ssh-copy-id sio-gcastillo@geo-new.ucsd.edu
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
Password: 

Number of key(s) added:        1

Now try logging into the machine, with:   "ssh 'sio-gcastillo@geo-new.ucsd.edu'"
and check to make sure that only the key(s) you wanted were added.

This can also be achieved manually by copy-pasting the public key and appending it to ~/.ssh/authorized_keys

You can login using the key. It can sometimes be helpful to tweak the SSH client configuration in your home directory, ~/.ssh/config