How do I secure a database ie*.gdb file?

I've searched the group and most of the talk I found was on securing the
server. My *.gdb file makes part of a distributable package, and anybody can
get to the data in the *.gdb, and I need to secure it as with *.mde files
for access databases. The hard work lies in structuring the data to make it
usable, and if anybody can get his hands on this, then it makes all my work
a waste of time!

Once the *.gdb file in question has been copied or backed up, anybody with a
SYSDBA password on another Interbase server, can have insite into the data,
and database structure.

This would appear a serious threat to ones data, especially if it is
sensitive eg: Medical, Banking data.
Access to the data on a single server is controlled by isc4.gdb, so on the
server it is safe, but once a person has a copy of the *.gdb, he can open on
his own pc with his own isc4.gdb, and the *.gdb is no longer secure.

All answers will be appreciated.

Thanks in advance

Adrian Wreyford