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