Copy protection schemes...
1. Hard disk serial no. This number is stored on the hard disk boot sector
and can easily be changed. IMHO, it is better to write a hidden file on the
hard disk. Name this file so that it resembles a system file, eg.
MSSOFT.SYS, and put it in the system / system32 directory.
2. Network card MAC address. Will not run on machines without a network
card. What about machines with multiple network cards? What happens if the
network card gets blown to pieces by a lightning strike? Furthermore, some
cards allow the MAC address to be changed.
3. CPU unique ID. Will only run on Pentium III systems.
4. Dongle. Has hardware compatibility problems - eg. some printers will
not work with a passthrough dongle.
5. Soft sector floppy - this is a very old technique that involves creating
a sector on a floppy that cannot be copied by the normal DOS copy command.
Bulk disk copy machines can easily copy this sort of disks.
In any case, *ALL* copy protection schemes, no matter how elaborate, can be
broken. This includes the hardware dongles. (All you need is a good
debugger and a hex editor). They only work to deter the casual pirate, not
the professional ones. Once broken your software is copied for the cost of
a CD.
Genuine users are usually encumbered by elaborate schemes. I want to run an
install program and expect software to work - I don't want to have to fiddle
with hardware devices, etc. I want to be able to reinstall my hard disk
when I upgrade and expect the software to still work.
IMHO, the best copy protection is support. If your customers rely on your
support and they shall not copy your software! I.e., sell not only
software, but service.
If you are selling to the low end market (that does not warrant support),
make it *VERY* cheap - so as to make it unattractive to pirate (eg. why buy
pirated for $5 when you can buy the real thing for $20). Put it on a CD,
and make it so that it can only be installed from a CD. When installed, it
puts files all over the machine - so one cannot just copy the install
directory and expect it to run. Provide a printed manual - printed matter
is more costly to pirate, especially if it is in colour. Provide regular
updates - eg. make your users subscribe to the software and provide
quarterly updates. Make each version work only for a limited period (eg.
one year). Put the date code in different places for different updates.
It is always difficult to juggle the cost of copy protection against the
loss of revenue from pirating.
Lastly, consider this: The more copy protection you put in, the more
temptation you give hackers to break your copy protection scheme. Once
broken, it is usually posted all over the internet and pirate BBS.
Regards,
Dennis.
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