ssh-keygen -t rsa -b 4096 ssh-keygen -t dsa ssh-keygen -t ecdsa -b 521 ssh-keygen -t ed25519
/etc/ssh/ssh_host_dsa_key /etc/ssh/ssh_host_ecdsa_key /etc/ssh/ssh_host_ed25519_key /etc/ssh/ssh_host_rsa_key