SSH Key Authentication with PuTTYgen

SSH key authentication is more secure than password authentication and allows for passwordless login. This guide shows how to generate and use SSH keys with PuTTYgen.

Why Use SSH Keys?

• More secure than passwords
• Eliminates password brute-force attacks
• Enables automated scripts and deployments
• No need to remember complex passwords

Generating SSH Keys

1. Download and launch PuTTYgen
2. Select "RSA" key type and 2048 or 4096 bits
3. Click "Generate" and move your mouse randomly
4. Add a passphrase for extra security (optional)
5. Save the private key (.ppk file)
6. Copy the public key text

Installing Public Key on Server

To install the public key on your server:

1. Connect to your server via SSH
2. Create the .ssh directory: mkdir -p ~/.ssh
3. Edit the authorized_keys file: nano ~/.ssh/authorized_keys
4. Paste your public key on a new line
5. Set proper permissions: chmod 600 ~/.ssh/authorized_keys

Using SSH Keys with PuTTY

1. Open PuTTY Configuration
2. Go to Connection → SSH → Auth
3. Browse and select your private key (.ppk file)
4. Return to Session tab and save your configuration
5. Connect to test the key authentication