Date stamp a stack

[Bill Marriott]

Bill,

> It is for licensing. I was thinking that this would be a good method for a 
> limited time trial of my software. The document stack  would contain the 
> user's data and the program would check the creation  date of the data 
> stack for the trail period. Once the user paid for  the software it would 
> no longer care what the creation date was.

RevSelect recently released Zygodact, which does this exact thing:

http://www.runrev.com/products/related-software/zygodact/

...and it's part of the holiday megabundle, too:

http://www.runrev.com/offers/megabundle08/index.htm

So you could get it "free" along with hundreds (to thousands) of dollars of 
other great add-ons and your Rev software assurance (updates) for a year. 
[Not to mention supporting Jacqui and the other great contributors to this 
list who are part of revSelect.]

Now that I know what you're doing -- if you really want to do this on your 
own instead of using a nice, tidy, complete, professionally produced, 
well-documented and well-tested package like Zygodact -- other thoughts 
comes to mind:

- storing the information in the registry (on Windows) or some analogous 
hidden spot on Mac. Again, using encryption and/or an md5 checksum to record 
the value.

- doing what Rev does and using a "trial" key which has the expiration date 
encoded within it. Users can't run the software without such a key; and they 
can't cook up a new key on their own.

- having some sort of online activation where the trial app "phones home" to 
your server, which has information unique to the installed system/user and 
expiration date.

Good luck,

- Bill

[sorry for the near-duplicate; hit ctrl-enter prematurely by mistake]