ssh-keygen -o -a 100 -t ed25519
OSSEC is an Open Source Host-based Intrusion Detection System that performs log analysis, file integrity checking, policy monitoring, rootkit detection, real-time alerting and active response.
sshfp generates DNS SSHFP records from SSH public keys. sshfp can take public keys from a known_hosts file or from scanning the host's sshd daemon.