Bill Stewart wrote:
Music Hoarders have a somewhat harder problem, in that they want to copy-protect information while providing near-identical copies to large numbers of people, while you're more likely to want to provide your personal transaction information or private messages only to a small number of recipients - but you may still want some kind of watermarking to identify who sold your "private" information to somebody you didn't authorize.
putting watermarking aside, this is the core. the normal use for encryption is to make sure only a few people can access the information. the movie/record/content "protection" purpose is not, you still want to distribute your stuff high and wide, to as many people as possible. you can say "authorized access" in both cases, but it has a different meaning. both "root" and "ftp" ask for a password when you log into the FTP server, but they're hardly on the same level. therefore, software (and hardware) does and needs to work differently in these cases. you don't use PGP for DVDs, you invent CSS. I do think these things are farther apart than they appear. what it boils down to is that the "protection" scheme doesn't seriously want to stop anyone accessing the content. what it really wants is to make sure he's following the rules (such as paying a fee). this is more an authorization/permission system than an encryption one.