[AccessD] How to set up a license key for an Access FE/BE system?

Dan:

I did this for my manufacturing system.  I have several pieces of
information stored in it and it's fifteen characters.  I group them three at
a time for the user to input into the program to renew the license, so it
looks kind of like a Microsoft registration key.  

What I did for the expiration date was fairly simple - OK real simple - I
took the month of expiration and converted it to a letter, took the day of
expiration and converted it to two letters because it could go up to 31, and
converted the year of expiration to a letter as well, selecting a base year
far enough back so that the expiration year would not always be A or B but
would start further down the alphabet.  And added constants to a couple of
these number to make decryption even harder - but that is probably overkill.

I then scattered these three values in the key.  I have a routine in the key
maker that creates a key, and a routine in the product which decodes the
key.  

Simple but effective enough for my purposes.  There are several 'garbage'
characters in the key and those are generated randomly.  So comparing keys
over a period of years (assuming anyone had that interest) would be
difficult.  

Finally, one of the characters is a checksum.


HTH

Rocky

P.S.  Often wondered what scheme Microsoft was using and what information
they had encrypted in their key.

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Dan Waters
Sent: Sunday, March 07, 2010 9:09 AM
To: 'Access Developers discussion and problem solving'
Subject: [AccessD] How to set up a license key for an Access FE/BE system?

I'd like to learn how to set up an encrypted license key mechanism for a
customer using a split configuration system.  The key would allow the system
to work until a specified date.

What could I look at to learn how to do this?

Thanks!
Dan


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