>  Even if you can't find a CRC equation which lends itselt
 > to calculating the value to pach into it, if you only
 > include the checking routine on the final release
 > version, then you can always leave a program running all
 > night, trying to figure out the right value.

Steven, this won't work. A circular dependancy can only be resolved if
there is an equilibrium, but there's no guarantee in the CRC algorithm that
such an equilibrium exists. You might even get to the situation where one
value placed in the executable results in another value that needs to be,
and placing that one there results in the other; ie. no resolution. More
likely, you'll get a far more elaborate 'circle' of any number of values
which has no resolution whatsoever.


 > If the CRC
 > (or preferably the value needed to get the CRC to a
 > specific value) is stored at the end, then the patching
 > program could simply get the crc up to that point, and
 > would only need to recalculate the crc of the code it's
 > trying.  Leave it running overnight, and you should have
 > a program ready to distribute by morning.

It might also take several years. It might also never happen. Chances are
that the latter will be true.


 >  Also, you could use the program's CRC to decode the
 > registration key, extracting a "control" section which

What's this hangup with CRCs? They's nothing particular holy about them,
and there are far better (and cheaper) hashing algorithms in existance,
certainly there are far better encryption algorithms.

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