freebsd security - Sep 2003 - Question about world read permissions on system level files

All,

I need to trim the world read permissions from the system sensitive files. I
know that it would be safe to trim the permissions from many of the
configuration files in /etc. But I was not sure if I could safely tighten the
permissions form other system files. Does any one know of any documentation on
this. Or can any one tell me if it is safe to trim world read permissions from
the system files.

Thanks in advance,
Urvi