jbn@wdl1.UUCP (John B. Nagle) (05/15/84)
Uncrackable protection may be difficult, but for small-volume software,
it is possible to encode serial numbers in the software in an untamperable
way, if it is worth the trouble to you. The easiest way is to relink the
program for each copy made, with the serial number of the program expressed
as a permutation of the order of linking. This will cause each copy of the
program to be vastly different from each other, because the reordering
takes place before relocation is applied during linking, so the program
is not only rearranged, but the sections differ.
Only worth the trouble if you have a low-volume, high-priced product
and you intend to sue pirates.