Generate an SSH Key Pair

Generate the key pair

Run the following command to create a new SSH key pair using the Ed25519 algorithm:

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

Ed25519 is the recommended algorithm—it's faster, more secure, and produces shorter keys than RSA. The -C flag adds a comment (typically your email) to help identify the key later.

When prompted for a file location, press Enter to accept the default (~/.ssh/id_ed25519). You'll also be asked for a passphrase—adding one provides an extra layer of security in case your private key is ever compromised. You can leave it empty for convenience, but a passphrase is strongly recommended for production use.

Verify the key was created

Confirm that both files were generated:

ls -la ~/.ssh/id_ed25519*

You should see two files:

• id_ed25519 — Your private key. Never share this file with anyone. Its permissions should be 600 (owner read/write only).
• id_ed25519.pub — Your public key. This is safe to share and is what you'll copy to servers and services.

Copy the public key to your target

Display your public key:

cat ~/.ssh/id_ed25519.pub

For a remote server, the easiest method is ssh-copy-id, which appends your public key to the server's ~/.ssh/authorized_keys:

ssh-copy-id user@server

For GitHub, copy the output from cat above, then go to Settings → SSH and GPG Keys → New SSH Key and paste it in.

After adding the key, test the connection:

ssh -T git@github.com

You should see a message confirming your identity.