How to Set Up SSH Keys for GitHub (All Platforms)

If you’re still cloning repos with HTTPS and typing your password — or using a personal access token — this guide is for you.

SSH keys are faster, more secure, and once set up, completely invisible. You just run git push and it works.

Step 1: Generate an SSH Key

The command is the same on all platforms (macOS, Linux, WSL on Windows):

ssh-keygen -t ed25519 -C "your@email.com"

Use the same email you use for GitHub. When prompted:

File location: Press Enter to accept the default (~/.ssh/id_ed25519)
Passphrase: Enter a passphrase (recommended) or press Enter for none

This creates two files:

~/.ssh/id_ed25519 — your private key (never share this)
~/.ssh/id_ed25519.pub — your public key (what you give to GitHub)

Note: If you’re on a very old system that doesn’t support Ed25519, use RSA instead:
ssh-keygen -t rsa -b 4096 -C "your@email.com"

Step 2: Add the Key to ssh-agent

The ssh-agent holds your key in memory so you don’t have to type your passphrase every time.

macOS

eval "$(ssh-agent -s)"
ssh-add --apple-use-keychain ~/.ssh/id_ed25519

The --apple-use-keychain flag saves the passphrase to macOS Keychain automatically.

Also add this to ~/.ssh/config (create the file if it doesn’t exist):

Host github.com
  AddKeysToAgent yes
  UseKeychain yes
  IdentityFile ~/.ssh/id_ed25519

Ubuntu / Linux

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519

To make this persist across sessions, add to your ~/.bashrc or ~/.zshrc:

# Start ssh-agent if not running
if [ -z "$SSH_AUTH_SOCK" ]; then
  eval "$(ssh-agent -s)"
  ssh-add ~/.ssh/id_ed25519
fi

Windows (native — Git Bash or PowerShell)

# Enable and start the ssh-agent service
Get-Service -Name ssh-agent | Set-Service -StartupType Automatic
Start-Service ssh-agent

# Add your key
ssh-add $env:USERPROFILE\.ssh\id_ed25519

Windows (WSL — Ubuntu inside Windows)

WSL behaves like Ubuntu. Use the Linux instructions above.

Step 3: Copy Your Public Key

You need to give GitHub your public key (the .pub file):

macOS

pbcopy < ~/.ssh/id_ed25519.pub

Ubuntu / Linux

# Install xclip if not available
sudo apt install xclip

xclip -selection clipboard < ~/.ssh/id_ed25519.pub
# or just print and copy manually:
cat ~/.ssh/id_ed25519.pub

Windows (Git Bash)

clip < ~/.ssh/id_ed25519.pub

Windows (PowerShell)

Get-Content $env:USERPROFILE\.ssh\id_ed25519.pub | Set-Clipboard

Step 4: Add the Key to GitHub

Go to github.com and log in
Click your avatar → Settings
In the left sidebar: SSH and GPG keys
Click New SSH key
Give it a title (e.g., “MacBook Pro” or “Work Ubuntu”)
Paste your public key
Click Add SSH key

Step 5: Test the Connection

ssh -T git@github.com

You should see:

Hi username! You've successfully authenticated, but GitHub does not provide shell access.

If it says Permission denied, see the troubleshooting section below.

Step 6: Clone with SSH (not HTTPS)

Now use SSH URLs when cloning:

# SSH (use this now)
git clone git@github.com:username/repo.git

# HTTPS (old way — requires password/token)
git clone https://github.com/username/repo.git

For repos you already cloned with HTTPS, switch them:

cd myrepo
git remote set-url origin git@github.com:username/repo.git

# Verify
git remote -v
# origin  git@github.com:username/repo.git (fetch)
# origin  git@github.com:username/repo.git (push)

Multiple GitHub Accounts (Work + Personal)

If you use two GitHub accounts on the same machine, you need separate keys and an SSH config to route them correctly.

Generate a second key

ssh-keygen -t ed25519 -C "work@company.com" -f ~/.ssh/id_ed25519_work

Add the work key to your work GitHub account (same Step 3–4 as above).

Configure `~/.ssh/config`

# Personal GitHub
Host github.com
  HostName github.com
  User git
  IdentityFile ~/.ssh/id_ed25519

# Work GitHub
Host github-work
  HostName github.com
  User git
  IdentityFile ~/.ssh/id_ed25519_work

Use the alias when cloning work repos

# Instead of: git clone git@github.com:company/repo.git
git clone git@github-work:company/repo.git

Git sees github-work and uses your work key. GitHub sees your work account. It routes correctly.

Troubleshooting

”Permission denied (publickey)”

# Debug the connection
ssh -vT git@github.com

Look for:

“Offering public key” — which key is being tried
“Server accepts key” — connection succeeded
“Permission denied” — key not on GitHub, or wrong key being offered

Common fixes:

# Make sure the key is loaded
ssh-add -l

# If not listed, add it
ssh-add ~/.ssh/id_ed25519

# Make sure permissions are correct
chmod 700 ~/.ssh
chmod 600 ~/.ssh/id_ed25519
chmod 644 ~/.ssh/id_ed25519.pub
chmod 644 ~/.ssh/config

“Too many authentication failures”

Your agent is trying too many keys. Add this to ~/.ssh/config:

Host github.com
  IdentitiesOnly yes
  IdentityFile ~/.ssh/id_ed25519

“ssh-add: Could not open a connection to your authentication agent”

The agent isn’t running:

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519

On Windows — “WARNING: UNPROTECTED PRIVATE KEY FILE!”

# Fix permissions in PowerShell
icacls $env:USERPROFILE\.ssh\id_ed25519 /inheritance:r
icacls $env:USERPROFILE\.ssh\id_ed25519 /grant:r "$env:USERNAME:R"

Summary

# The whole setup in one place:
ssh-keygen -t ed25519 -C "you@email.com"
eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519
cat ~/.ssh/id_ed25519.pub   # copy this → GitHub Settings → SSH Keys
ssh -T git@github.com       # test it

Once SSH is set up, you’ll never touch a personal access token again.

Don’t have Git installed yet? Start here: How to Install Git on Ubuntu, macOS and Windows.

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