It must be secure, unless ofcourse if your database isn't secure (db password must not be readable for users).

The back end of the whole thing is a whole other thing. Our IT people will probably just want to use a .dat file in an obscurely-named folder in /cgi-bin, knowing them. As long as the script doesn't ever give a CGI::Carp type error saying it couldn't find it, that's probably secure enough anyway ... right..?