Trial Version Code

B

box2003

Does anyone have a lead on a code segment that could be put into an
application to permit a trial version use period for an application? For
example, users have 15 days to use application free, then must purchase and
obtain key, or application fails to launch? What I presently do is keep a
running count on some table value that provides a user with a message that
trial use limitations have been reached. Or one other method I use is
compute date math from an embedded date in code, when number of days is
reached, application message displays, application shuts down. In both
cases, users are using an *.mde build.

Would it be better for to write a key to the registry and compute date math
with a date value in the key? This is the part I do not know about and need
direction to where I might find information.
 
T

Tony Toews

box2003 said:
Does anyone have a lead on a code segment that could be put into an
application to permit a trial version use period for an application? For
example, users have 15 days to use application free, then must purchase and
obtain key, or application fails to launch?

Tools available from sites such as sysinternals.com can crack any
method you use to store a future date anywhere on a system such as in
the registry or a file. Unless it's encrypted. But even then if you
delete the date from wherever it's stored your app may think it's just
installed.

Thus I prefer to limit the number of records in one key table such as
5 units or 50 volunteers but allow unlimited access for everything
else. Once I get paid then I email them an encrypted file containing
the number of records they are licensed for as well as their company
name which goes on the bottom of every page of every report.

For more of my thoughts on this topic see the "Copy protection or how
to safely distribute a demo Microsoft Access Application" page at
http://www.granite.ab.ca/access/demo.htm

Tony
--
Tony Toews, Microsoft Access MVP
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