The password protect ion on a workbook/worksheet is not very good there are
programs on the web as you found out the can break the password in minutes.
I've done it myself on a protected sheet to find out how cells were
calculated.

"Jeremy" wrote:

I have prepared a pretty advanced spreadsheet to give to a potential
customer. Because this customer does not have an exclusive agreement with my
company, I would like to build in some security so they cannot see the
calculations and base values.

I tried to hide the sheet with the calculations and protect it. On of our
sales guys was able to break this open in less than 20 minutes.

How can I better secure this?