How to set trial?

B

Brett

If some one is selling Excel Add-Ins and offer a trial version, how
are they doing that? If I create an Add-In, how to I set it for a
trial? Meaning at some point, it locks the person out until they
register it.

Thanks,
Brett
 
B

BrianB

You can check the current date of today (using the VBA Date function
against a coded date or cell content
 
B

Brett

Will hiding and locking the cell with the expire date then password
protecting the sheet be enough to keep some one from invalidating the
trial? Is there a better way?

Thanks,
Brett
 
B

Bob Phillips

Brett,

No there is no secure way in Excel and/or VBA to do this. All of the locking
mechanisms are easy to break.

--

HTH

Bob Phillips
... looking out across Poole Harbour to the Purbecks
(remove nothere from the email address if mailing direct)
 
B

Brett

If the sheet is protected by password, how does some one unlock it
without having the password?

Why does the sheet protection exist if it doesn't supply security?

Brett
 
J

Julian Milano

Why are 15 yo boys able to hack into NASA and move satellites around in
space?

XL is as protected as <cough> it's makers made it. But there exists very
intelligent programmers out there who can do wonders (Hi Mom!). I class MS
security as BASIC. It keeps the no-brainer worker out of mischief but if
someone is dedicated, then they should get in!
 
B

Bob Phillips

Workbook and worksheet passwords are easy to break. Even if someone doesn't
have the skills themselves, a quick search of Google throws up many
solutions.

Add-ins are a bit more difficult, but not too much so, still breakable
relatively easily.

Next step is a dll, but this is heavier programming, and real hackers will
crack this as well if they really want to.

Afraid Excel and VBA protection will only stop the casual snooper, or those
too lazy to take it any further.

--

HTH

Bob Phillips
... looking out across Poole Harbour to the Purbecks
(remove nothere from the email address if mailing direct)
 
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