Which program to use to protect my workbooks

[theojanissen]

I created a workbook that will be distributed and used by hundreds of people within my organization. The workbook contains macro's and sheets that I have protected within Excel itself, using passwords on sheet level, workbook level and VBA level. I don't want the users to get acces to the intelligent part of the workbook and know that the Excel protection mechanism is not enough to do teh job due to teh fact that tools are available to open an Excel protected workbook everywhere. On the internet I found several suppliers of programs that say that they deliver this kind of protection services. My question is, what is a proven good supplier/program that does the job? Thanks, Theo