CD-ROM software "shopping"

I picked up a new Mac this weekend (a Quadra 650, on the very eve of
its obsolescence :-) and with it came a CD from "Software Dispatch"
(or something like that) packed with commercial software, and
apparently locked with some sort of cryptographic protocol.

I'm not sure whether each CD is digitally stamped with a key (seems
kinda difficult) or whether the key I typed in from the cardboard
envelope at the start-up screen served the purpose of identifying my
disk (probably).  You call up an 800 number and give them a key from
the disk (I can't remember whether it was the same as the key I typed
in) and after supplying a credit card number they'll "unlock" whatever
packages you want by providing another key for each one.

Does anybody know what sort of protocol this is using?  The keys are
pretty long (about 16 bytes).  (Note that I'm really just curious; I
don't think I have the attention span to try and "break" it.  Besides,
I already bought the only things I wanted off it :-)

--
| GOOD TIME FOR MOVIE - GOING ||| Mike McNally <m5@tivoli.com>       |
| TAKE TWA TO CAIRO.          ||| Tivoli Systems, Austin, TX:        |
|     (actual fortune cookie) ||| "Like A Little Bit of Semi-Heaven" |

RE: Software Dispatch CD...
  
While each individual CD doesn't have a unique key, each batch does.
From what I heard, on the average, there are 10 separate batch/keys.
So if your friend buys X software off his CD and gives you his key
you have a 1 in 10 chance of being able to get the software...

(Kinda useless, if you're going to pirate it, you just copy the
software, but at least it prevents the serial number lists from
hawking the cd-wares...)

Also, I think the key they give you contains a private reg. number
so if you spread the software you buy they can track you down and
hunt you like a dog... :-)

Then again, there's nothing preventing you from running a hack
program on the CD (other than time of course...)