SSH Key-Based Authentication

Configure SSH key auth on a Linux server.

Steps

1. Generate a key on your local machine:

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

2. Copy the public key to the server:

   ssh-copy-id <user>@<server>
   # or manually append the public key to ~/.ssh/authorized_keys

3. Secure permissions:

   chmod 700 ~/.ssh
   chmod 600 ~/.ssh/authorized_keys

4. Optional: disable password authentication in /etc/ssh/sshd_config:

   PasswordAuthentication no
   ChallengeResponseAuthentication no
   UsePAM yes

   Then reload:

   sudo systemctl reload ssh