Abstract

To enhance the security of my cloud servers and Mac exposed to the public internet, I plan to replace all password-based authentication with SSH key-based authentication.

Method

1. Generate SSH Key Pair

You can easily generate an RSA 4096-bit key pair using a terminal on macOS, Linux, or Windows:

ssh-keygen -t rsa -b 4096 -C "your_email@example.com"

After executing this command, you will get two files (by default in ~/.ssh/):

• id_rsa: your private key (keep it safe!)
• id_rsa.pub: your public key

2. Deploy the Public Key

To enable key-based login, append the public key to the authorized_keys file on the target server:

cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys
chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys

Make sure you're operating on the correct user's .ssh folder on the server, not your local machine.

✅ Once you've done this, you should be able to log in to your server using your SSH key without a password.