SSH Server Hardening

This host's OpenSSH server ships with an insecure baseline: root may log in over SSH, password authentication is enabled, and the login-attempt limit is too loose. Harden /etc/ssh/sshd_config so it meets the site policy in /root/case/brief.txt: root must not be allowed to log in with a password, password authentication must be disabled everywhere (keys only), and MaxAuthTries must be tightened to the exact value your assignment specifies. Grading reads the durable sshd_config directives (what a config review or a restarted sshd would honour), so it is the file that must be correct, not a running daemon.