SSH-Keys?

• secure way to access remote machines without a password
• based on encryption

NEVER share the private key with anyone!

flowchart LR
    subgraph Local Machine
        priv@{ shape: rounded, label: "Private Key"}
        pub_loc@{ shape: rounded, label: "Public Key"}
    end

    subgraph Remote Machine
        pub_rm@{ shape: rounded, label: "Public Key"}
    end

    enc@{ shape: rect, label: "Encryption Math"}

    pub_loc -.->|upload once| pub_rm
    priv -->|login request| enc <-->|compare| pub_rm

Generating a Key-Pair

• see GitHub for details

#generate a key-pair
ssh-keygen -t ed25519 -f <key filename> -C <your email/user>                                                    

#content of ~/.ssh/config
Host <shortcut to use for connecting>
    HostName <host address>
    User <username>
    ForwardAgent yes
	ForwardX11 yes    #for interactive window forwarding
    IdentityFile <path to private key>
Host github #for github
    HostName github.com
    User git
    IdentityFile ~/.ssh/github                                                                           

• copying to remote host

ssh-copy-id -i <key filename> user@host                                                                         

SSH-Agent Not Running?

• activate

eval "$(ssh-agent -s)"                          #linux
Invoke-Expression -Command "$(ssh-agent -s)"    #windows 

• add key to session

ssh-add <key name>

SSH Agent Forwarding

• allows using of GitHub on OzStar
• add the following to your .bashrc (.bash_profile file)

echo "Setting up agent forwarding"      #make sure script talks to me
eval "$(ssh-agent -s)"                  #get agent
ssh-add ~/.ssh/github                   #forward github sshkey

• Testing (on OzStar)

ssh -T git@github.com

SSH and GitHub

• go to GitHub > Settings > SSH and GPG keys
• click new SSH key and follow instructions
• testing authentication

ssh -T git@github.com