Time Limitation (protection)

[MNE163]

Is there a way (using VBA) to add a time limitation to a worksheet or
workbook ? something like an EXPIRED TRIAL PERIOD ?

 

[J.E. McGimpsey]

Excel is not really able to do this securely. You can search the
archives:

http://google.com/advanced_group_search?q=group:*excel*

using the term "workbook expire" (without quotes) - you'll find
dozens of threads addressing the various approximations you can
make.

Just realize that any of those suggestions will only keep the naive
or uncurious from bypassng your method.

 

[Alan]

Can be done but only to the honest or uninformed. Excel passwords are quite
crude and easily cracked.
Regards,
Alan.

 

[BrianB]

1. Have sheets hidden & protected (only able to unhide with a macro)
otherwise can be viewed if macros disabled.

2. Have a macro in the Open event of the workbook to check the curren
date with one you decide and unhide the sheet

 

[J.E. McGimpsey]

Note that this can be bypassed easily by changing the system date.

The sheets would need to be hidden with the property xlVeryHidden or
they'll show up in the Format/Sheet/Unhide menu.

Also, once the workbook has been opened once, knowing the sheet
names allows the user to change the hidden status in the VBE the
next time, even if the workbook has "expired" (the sheet names are
also visible if you view the file in a hex editor).

 

[Dana DeLouis]

Just a gee wiz. I'm not that familiar with it, but Excel 2003 has
"information rights management (IRM) functionality." I don't know if it is
accessible thru VBA.

When you look under Excel, it says in part...
..Set expiration dates to provide a time limit after which a file can no
longer be opened.

I noticed a Print statement.

..Restrict file printing to reduce the number of hard copies being produced.

That question comes up every so often.

Information Rights Management in Office Professional Edition 2003
http://www.microsoft.com/office/editions/prodinfo/technologies/irm.mspx#XSLTsection127121120120

 

[J.E. McGimpsey]

Just note that in order to use IRM, you have to have Windows Server
2003 running with RMS activated.

 

[Harlan Grove]

Just note that in order to use IRM, you have to have Windows Server
2003 running with RMS activated.

...

Does that mean that it doesn't work at all in a purely Mac environment?

Are IRMed Excel files stored in some format other than the latest .XLS?

Tangential: recent versions of Adobe Acrobat have provided various levels of PDF
document security, but there are PDF to text programs written LONG AGO that
happily pull all the text out of protected PDF files. Formatting may be gone,
but content is still there. Unless there's some form of encrption involved, it's
hard to see how IRM would stand up to determined cracking.

 

[J.E. McGimpsey]

Does that mean that it doesn't work at all in a purely Mac environment?
Yes.

Are IRMed Excel files stored in some format other than the latest .XLS?

I've not seen any so I can't say...

Tangential: recent versions of Adobe Acrobat have provided
various levels of PDF document security, but there are PDF to
text programs written LONG AGO that happily pull all the text out
of protected PDF files. Formatting may be gone, but content is
still there. Unless there's some form of encrption involved, it's
hard to see how IRM would stand up to determined cracking.

I'd like to get a look at the specifications for how IRM is
implemented - none of my clients use it, or intend to.