brianjbayer/gist-mac-add-ssh-key.md

## gist-mac-add-ssh-key.md

      
    Raw
  

              gist-mac-add-ssh-key.md
            
          
    Add an SSH Key on a Mac

Add and configure an SSH Key to connect to remote source code
repositories (like GitHub) and servers.
⚙️ You can use an automated script to add an SSH Key
to your Mac.
I use a GitHub repository
mac-setup
for my basic Mac setup scripts including one to add a new SSH Key.
If you'd like, you can use my repository to add your new SSH Key.

 Just follow the PREREQUISITES
and then Add an SSH Key
of my GitHub repository

🛑 Once you add your new SSH Key to your Mac, you will
still need to determine how to add the new public SSH Key to
your remote server yourself.

Add an SSH Key on a Mac Manually

Here are the steps if you prefer to create and add a new SHH Key manually.

🙇 This is pretty much from the GitHub Documentation on
Connecting to GitHub with SSH

The overall process is...

Determine if you already have an SSH Key that you want to use
If not, generate a new SSH Key
Add your SSH Key to your SSH Config
Add your SSH Key to the SSH Agent
Add your public SSH Key to the host where you want to connect
Test the SSH connection

You will then need to add your public portion of your SSH Key to
where you are connecting like GitHub or your servers.
TL;DR:


Generate the key...
ssh-keygen -t ed25519 -C "your_email@example.com"

Add your SSH Key to your ~/.ssh/config file...
Host github.com
  AddKeysToAgent yes
  UseKeychain yes
  IdentityFile ~/.ssh/id_ed25519


Add your SSH Key to the SSH Agent
env APPLE_SSH_ADD_BEHAVIOR=macos ssh-add -K ~/.ssh/id_ed25519


Determine Your SSH Keys

Your SSH Keys should be located (even if by softlink) in your
~/.ssh directory.  To see what keys you have, simply list the
files in this directory.
ls -al ~/.ssh
They look something like this...
-rw-------   1 someuser  staff   464 Sep  3 14:41 id_ed25519
-rw-r--r--   1 someuser  staff   103 Sep  3 14:41 id_ed25519.pub


🙇 Checking for existing SSH Keys


Generate a New SSH Key


📧 You will need the email address that you want to be
associated with your new SSH Key

Encryption Algorithms

On Mac, you can generate the following types ( -t) of SSH Keys
(these are the encryption algorithms)...

dsa
ecdsa
ecdsa-sk
ed25519
ed25519-sk
rsa

The ed25519 algorithm is recommended.
Encryption Level (Bits)

You can specify the bit level of encryption using the -b option
(e.g. -b 4096 )
Generate

Here the ed25519 algorithm is being used...


In a terminal window, run the ssh-keygen command
substituting your email for "your_email@example.com"
ssh-keygen -t ed25519 -C "your_email@example.com"


When prompted to "Enter a file in which to save the key,"
You can press Enter to accept the default file location


When prompted to "Enter passphrase (empty for no passphrase),"
You can press Enter to select no passphrase


When prompted to "Enter same passphrase again:,"
You can press Enter to again select no passphrase


When the command finishes, you can verify that it was
created by listing your ~/.ssh directory
ls -al ~/.ssh


🙇 Generating a new SSH Key


Add your SSH Key to your SSH config


Ensure that you have an ~/.ssh/config file
touch ~/.ssh/config


Edit your ~/.ssh/config file using your
preferred editor


Add the following lines replacing github.com on the
Host line to the hostname where you are connecting
and ~/.ssh/id_ed25519 with the filename of your
IdentityFile (which is your new generated SSH Key)...
Host github.com
  AddKeysToAgent yes
  UseKeychain yes
  IdentityFile ~/.ssh/id_ed25519


🍎 macOS Sierra 10.12.2 or later, requires specifying
in your ~/.ssh/config file to automatically load keys
into the ssh-agent and store passphrases in your keychain


Save your ~/.ssh/config file with these changes


Add your SSH Key to the SSH Agent

You need to add your new SSH Key to the SSH Agent and your
passphrase to the macOS Keychain (if you added a passphrase to
your SSH Key)...


In a terminal window, run the ssh-add command
substituting your new SSH Key file for
~/.ssh/id_ed25519
env APPLE_SSH_ADD_BEHAVIOR=macos ssh-add -K ~/.ssh/id_ed25519

✨ The env APPLE_SSH_ADD_BEHAVIOR=macos environment
variable suppresses the warning messages about the -K option
being deprecated in newer versions of macOS.  The -K option
stores the passphrase in your MacOS Keychain


🙇 [Adding your SSH key to the ssh-agent](https://docs.github.com/en/authentication/connecting-to-github-with-ssh/
generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent#adding-your-ssh-key-to-the-ssh-agent)


Add Your Public SSH Key to the Remote Host

You will need to add your SSH Key to the remote host
where you want to connect, for example github.com.
You will use the contents of the *.pub version of your new
SSH Key file but the process for adding it to the remote host
will be unique to that host and/or organization.

To connect your SSH Key to GitHub, see their documentation
Adding a new SSH key to your account


Test the SSH Connection

If you are connecting to GitHub and have added your public
SSH Key to your GitHub account, here's how you can test your
SSH connection...


In a terminal window, run the ssh command
substituting your remote host for git@github.com
ssh -T git@github.com
You should see something like this as a response...
Hi someuser! You've successfully authenticated, but GitHub does not provide shell access.


🙇 Testing your SSH connection