SSH Keys, Tokens, and 2FA

Modern Git platforms (like GitHub and GitLab) support secure authentication mechanisms to manage repository access. SSH keys, personal access tokens (PATs), and two-factor authentication (2FA) play a critical role in safeguarding your work.

1. SSH Keys

SSH keys offer a secure, password-less way to authenticate with Git remotes over SSH.

a. Generate an SSH Key

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

This creates a public and private key pair in ~/.ssh/.

b. Add Your SSH Key to the SSH Agent

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

c. Add the Public Key to GitHub

Copy the contents of your public key:

cat ~/.ssh/id_ed25519.pub

Paste it into: GitHub > Settings > SSH and GPG Keys > New SSH Key

2. Personal Access Tokens (PATs)

With HTTPS-based Git remotes, password authentication is no longer supported. Instead, use Personal Access Tokens.

• Tokens act like passwords with limited scope and expiration.
• Can be used in Git clients, CLI, or API access.

a. Generate a Token (GitHub)

GitHub > Settings > Developer Settings > Personal Access Tokens

Choose scopes such as repo, workflow, or admin:org.

b. Use with HTTPS

When prompted for a password during git clone or git push, paste your token instead.

You can also embed it in your Git remote URL:

https://<username>:<token>@github.com/username/repo.git

3. Two-Factor Authentication (2FA)

2FA adds a second layer of protection beyond just a password.

• Typically uses TOTP apps like Google Authenticator or Authy.
• Prevents unauthorized access even if your password is compromised.

a. Enable 2FA (GitHub)

GitHub > Settings > Password and Authentication > Two-Factor Authentication

Scan the QR code with your TOTP app and save recovery codes.

Summary