At 12:58 20/03/2001 -0600, David L. Nicol wrote:
>Nathan Russell wrote:
>
> > I might note that it's impossible to encrypt something so it cannot
> > be copied exactly; even now, it is very common for pirate DVD
> > manufacturers to simply copy the original disc byte for byte, without
> > even needing to crack the encryption.
>
>I guess "grey bits" never caught on. "Grey bits" were a copy-protection
>mechanism in which parts of the original media a program is distributed on
>were encoded poorly, so that repeated reads of the grey sections would
>produce different results. Before running, the program would try to read
>the grey section until something came up different.
Illegally encoded sectors are a common feature of current CD protection
schemes. I do not know whether they use "grey" bits, but they sure make it
impossible to play SOME (legally bought) games on SOME CD players.
(my favourite was the Red Alert CD that would play fine in the computer's
CD player, but would crash the machine if inserted in the same computer's
DVD player.....not pleasant.)
--
Harald Tveit Alvestrand, [EMAIL PROTECTED]
+47 41 44 29 94
Personal email: [EMAIL PROTECTED]
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