how to implement a activation code?

[Bill Marriott]

There are many, many ways to do this.

Some of them would involve the standalone "phoning home" to a server which, 
would enable or disable the software.

Another method would be to encode the expiration date into the activation 
code itself. For example if you wanted it to work the way Revolution does, 
with a user emailing in to request a key. The code "knows" when it expires.

A third way is to hide something in the registry (Windows) or somewhere 
on-disk where it's not easy to be found.

Here's a very very simple (and thus, easily "cracked") algorithm:

suppose the expiration date is "8/2/06"

the result of

base64encode(compress("8/2/06")) is

H4sIAAAAAAAAA7PQN9I3MAMAKw61YwYAAAA=

8/3/06 is H4sIAAAAAAAAA7PQN9Y3MAMATmkJ2wYAAAA=

9/2/06 is H4sIAAAAAAAAA7PUN9I3MAMAjt3pqAYAAAA=
11/24/09 is H4sIAAAAAAAAAzM01Dcy0TewBAC5rlHDCAAAAA=

Not that while some characters are the same, there's no "obvious" 
human-readable pattern.

Also, it turns out that the

"H4sIAAAAAAAAA" prefix and the "AAAA=" suffix are the same for all values 
encoded this way. So, your activation code could be:

7PQN9I3MAMAKw61Yw

In the standalone you would add use something like

put "H4sIAAAAAAAAA" into daPrefix
put "AAAA=" into daSuffix
put decompress(base64decode(daPrefix & daCode & daSuffix)) \
  into daExpireDate
if daExpireDate > the date then
  answer "Your trial period is over"
  quit
end if

There are many other, better ways you could "encode" a date (and other 
information) into an activation code. This is just one idea. The simplest 
code of all could be just three letters:

numtochar(month + 32) & \
  numtochar(day+ 32) & \
  numtochar(year - 2000 + 32)

Of course, people might guess that.



"Robert Mann" <robmann at gp-racing.com> wrote in 
message news:JPEJKOGMGBLMGMPIHNKCOEIKEPAA.robmann at gp-racing.com...
> Is there a sample of how to implement a activation code and or a limited
> number of trial days with a standalone build?
>
>
> Robert Mann