Password settings and file permissions

Hello all, Running yast command and then go to security settings we can set our password to use MD5, DES .... Which one is the best MD5 or DES? and why? And as for "Miscellaneous settings", I see "Setting of file permissions: Easy, Secure, Paranoid" and I do not know which one is the best. As for "User launching updatedb: nobody, root" and I do not know which one is best for security reasons. Thank you so much for your assistance. Best regards, Chan Choth