Lock the copies of the spreadsheet file away in a secure cupboard (and lock
the backups away in another secure cupboard). If you want to be very
careful, encrypt the files.

The protections within Excel itself aren't sufficiently secure to stop
someone determined from cracking them. If you look at the archives of this
group you will see how often people forget passwords for their files, and
how easily they (or anyone else who has access to the files) can find how to
crack them.

If you don't want someone to have access, don't let them near the files.
--
David Biddulph

"JBW" wrote in message
...
I have written a very detailed carbon footprint calculator for a large
packaging company and we're just about to go through third party
accreditation.

We now want to enable other users to make use of it.

How can we do this and protect it from being copied, sent, emailed etc