You could check out the info found he

http://www.cpearson.com/excel/WorkbookTimeBomb.aspx

But the bottom line is that if intellectual property, trade secrets,
etc, is important to you,
Excel should not be your development environment. It simply isn't
equipped for the kind
of security you need. Try VB6 -- a decompiled VB6 program boils down
to machine/assembler
code (if I remember my lessons correctly) which basically makes it
unreadable.

I'm curious, what kind of code does the spreadsheet have that couldn't
be found online somewhere?

--JP

On Sep 22, 11:42*am, travis wrote:
I've got a spreadsheet which I'm about to start leasing to paying
users. *I want to create a fully functional demo version that will
lock up after a period and have its formulas and especially its VBA
code obscured and protected against copying.

Knowing how easy it is to crack the password on spreadsheets, I know
that just putting a standard password on it isn't going to do much.

So what are my options?

I know about time bombing, and about inserting various date sensitive
bugs in cell formulas =if(today()bombdate,cause error,formula), but I
want to make it harder to copy.

I'm most concerned about hiding the VBA. *If I can lock up the VBA
somehow so the code can't be viewed or copied that would protect the
most valuable parts of the intellectual property.

Travis