Miakoda Apr 9
I have what I fear may be a stupid #Linux question...
If I set up an ssh key, upload it to the server, and then disable password login...
When I want to ssh from another machine? How would I then upload that key to the server?
Show threadJason StuartApr 9

@hellomiakoda So the private key portion you use to authenticate against the public key portion which is uploaded to the server is supposed to be the portable secured portion. Basically that would be secured on a hardware token or encrypted USB. And you'd be able to move that from machine to machine but never copying the private key to a foreign machine.

So what is your use case, I might be able to add more clarity if I understand how you're planning to use it.

EDIT: Just re reading this and I've confused myself now. So even I need to re-read how it works LOL.

Show threadMiakoda 
@JSCybersec I'm trying to set it up for local machines that don't really need the extra security, so that I can learn and understand this overlooked section of Linux knowledge
Apr 9 at 1:55pmWeb
Show threadJason StuartApr 9

@hellomiakoda Okay, so on each machine you want to connect to you add the publickey portion into the authorized_keys file for the user you're connecting as. Then the machine you're connecting from has to have the private key in the ssh profile (usually under the user home directory ~/.ssh

Then when you connect to the machine using your key.

So say on "remote" machine I am user bob and on local machine I'm user bobmcbobberson.

On remote machines bob profile I open the authorized_keys file under the bob/.ssh folder and add my (bobmcbobberson) public key text into it)

Then on my local machine I ssh into the remote machine -> ssh bob@remotemachine

Depending on your key you might need to type a password to open the private section which will authenticate against the remote machine. If it prompts you for a password to connect to the remote machine then password auth is still enabled

Show threadJason StuartApr 9
@hellomiakoda @nixCraft has some good tutorials that more than likely explain it better than I do >.< https://www.cyberciti.biz/faq/how-to-set-up-ssh-keys-on-linux-unix/
How To Set up SSH Keys on a Linux / Unix System - nixCraft

Explains how to set up SSH Keys for public key authentication on a Linux, FreeBSD, OpenBSD, OS X/macOS or Unix based systems.

nixCraft
Show threadMiakoda Apr 9
@JSCybersec Yeah, I did know keys can have a password to decrypt the key.
See, I thought there was some master list of pub keys in the server. I didn't realize it was under ~/.ssh.
So if a key is compramised, that's where I remove it from. Ooooh, is that why the keys have user@client in them?! So I can find which one is what?!
Show threadMiakoda Apr 9

@JSCybersec Yeah, I just copied my key in to authorized keys myself, and it worked. Ok, this makes more sense now!

Which means I could easily put my keys in my password manager if I want.

Show threadMiakoda Apr 9
@JSCybersec If I'm understanding correctly...
If my friend wanted to give me ssh access to her server, I could safely give her my pub key. She can add that to authorized_keys. But that file would NOT give HER access to my machines that use that key pair. Yeah? I have that right?
Show threadJason StuartApr 9
@hellomiakoda That is correct.
Show threadMiakoda Apr 10
@JSCybersec Thank you very much, by the way. Whatever was different about your answers, it finally made it click for me. Now I understand that I can either have a different key for each of my computers, OR move 1 key between them.
For now, I have a different key on each, and I generated a separate extra key I copied in to my password manager that I can use if I lock myself out.
Show threadJason StuartApr 10
@hellomiakoda I'm glad it clicked for you 😁