Git SSH Setup: Secure Authentication for Remote Repositories

Why SSH Over HTTPS

HTTPS requires you to enter your username and password (or personal access token) for every push. SSH uses cryptographic key pairs — once configured, you never type credentials again.

Generating an SSH Key

ssh-keygen -t ed25519 -C "your.email@example.com"
# Follow the prompts (press Enter for defaults)

This creates two files:

• ~/.ssh/id_ed25519 — your private key (never share this)
• ~/.ssh/id_ed25519.pub — your public key (goes on the server)

Adding Your Key to the SSH Agent

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

Adding the Key to GitHub

cat ~/.ssh/id_ed25519.pub
# Copy the entire output

Go to GitHub → Settings → SSH and GPG keys → New SSH key. Paste and save.

Testing the Connection

ssh -T git@github.com
# Hi username! You've successfully authenticated.

Cloning with SSH

git clone git@github.com:username/repository.git

Use the SSH URL format (git@github.com:user/repo.git) instead of the HTTPS URL (https://github.com/user/repo.git).

Multiple SSH Keys

If you use multiple Git services (GitHub + GitLab + Bitbucket), use a config file:

# ~/.ssh/config
Host github.com
  HostName github.com
  IdentityFile ~/.ssh/id_ed25519_github

Host gitlab.com
  HostName gitlab.com
  IdentityFile ~/.ssh/id_ed25519_gitlab

Troubleshooting

# Verbose output shows every step
ssh -vT git@github.com

# Permission denied? Check your key is added to the agent
ssh-add -l

# Wrong key? Specify which one to use
ssh -i ~/.ssh/id_ed25519 -T git@github.com

SSH authentication is a one-time setup that saves thousands of password prompts over the life of your project.