Currently no
one knows (or is saying they know) how to encrypt 7800
 carts.
  
 Actually, I seem to recall that a guy in rec.games.video.classic has
 figured it out, but there hasn't been any practical application of it
 yet.  But I haven't read r.g.v.c in a LONG time, so things may have
 changed...
 I wish I could remember his name... he was one of the big cheese
 techie
 types in the newsgroup that was always hacking up weird stuff, so I
 don't
 doubt that he did it.
 -------
 My good friend, Bruce Tomlin, was the person who did that.
 -Mp