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Re: Timed demos [message #28270 is a reply to message #28266]

Wed, 25 August 2010 14:06

mdelfede
Messages: 1308
Registered: September 2007

Ultimate Contributor

Mhhhhh.... nope, again.
If the user erases the config file, put timer back and redo the config file from the original one, it's ok for him.
Yep, quite uncomfortable, but would defeat the purpose.

The only cheap way I see is to put in data files a small encrypted part containing last saving date and CRC of whole datafile.
BUT, then the user could not recover or modify by hand the datafile, ever, ad that's not what I need.

I think that what we need is a way to detect the changing of PC time in a reliable and portable way.

Thinking about it.... a partial solution would be to insert an encrypted date in datafiles, with CRC *ONLY* on it.
So user could edit the data by hand, but not touch at the encrypted part.... But again, if he's smart enough he could copy just the encrypted part and insert it on other files.

No more hints ? Rolling Eyes

Max

Edit : I should explain better what I want do to :

1) Put the app free to download, but limited in funcionality.
Just compiled with some missing part, impossible to crack, of course.

2) Offer the app for a monthy trial to registered users; the app gets username and expiring date hard-coded.
It's crackable, but limited to registered users.

3) Send the full-functional app without any protecton, just the user's data hard-coded on it, upon purchase.
I don't want to limit user to run it on many computers nor to have some dongle around.... Just want that who pay can use it and copy it, just have it's name on all printouts.

So, points 1 and 3 are easy, I just need a reliable way for point 2.

Max

[Updated on: Wed, 25 August 2010 14:10]

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