"S1" encryption system

[Hal]

Correction, I just noticed that the four F functions have 4 bit output
not 8 as I wrote.  Realize that all this is based on a very cursory
examination of the code.
 
BTW I just was starting to look at the key scheduling and I noticed that
fullkey is indexed in its 2nd slot by i*2 where i goes from 0 to 31, but
is only declared as being 32 in size in that slot.  So I think this is
another typo, probably the index should be i.  This kind of thing does
not inspire confidence...
 
Hal