Default permissions on Linux home directories

As noted in the manual by default home folders made with useradd copy the /etc/skel folder so if you change it's subfolder rights all users created after in with default useradd will have the desired rights. Same for adduser. Editing "UMASK" in /etc/login.defs will change the rights when creating home folders.

If you want more user security you can encrypt home folders and put ssh keys in /etc/ssh/%u instead of /home/%u/.ssh/authorized_keys .