feldon27 wrote;
[snip] ..and the Aquarium phoning home to check the validity of the keycode.
Sir. I feel the above would do far more harm than good.
IME, protection routines/algorithms are an double edged sword, the harder the nut to crack, the greater the temptation to crack it (and often, the more user-unfriendly software becomes.)
Speaking as an long time amateur C/ASM programmer, hardware dongle aside (and even then

) I have yet to dissect code that cannot be cracked, including that of multi-billion dollar corporations, with little dedication.
In short, don't bother wasting resources better spent elsewhere. Accept piracy exists, will
always exist, rather, strive to produce software
worth every penny.
Side-Note; How do I acquire Mr. Sachs widescreen aquarium?