On Fri, Jul 03, 2009 at 09:47:20AM -0400, Richard Stallman wrote: > You'd make me happy if I was able to access cable TV signals I have > paid for without DRM. > > I think it is not quite correct to call cable scrambling DRM. DRM > restricts the use of data you have a copy of. Cable scrambling > prevents you from getting the data if you do not pay for the > descrambler; however, as far as I know, once you do have the > descrambler, and do get the data, it does not seriously impede your > use of the data.
This is not correct (any more). With the advent of CI+ for DVB (the european-originated version of digital TV meanwhile used in several parts of the world), the cable operators have the possibility to only allow descrambling by CI+ capable receivers/descrambling modules. However, to be CI+ compliant, all receivers and descrambling modules have to be certified and have to authenticate against each other to prevent CI+-compliant operation if this authentication fails. This is necessary because the CI+ specification mandates that any receiver operating a CI+ descrambling module honors the operator-sent bits specifying what you are allowed to do with the "descrambled" signal: analog/digital outputs, store on a disk (the time to stay there can be limited by the operator), and so on. Needless to mention that you have to prove secure boot to get CI+ certification (and thus a valid certificate). There's much more to this, but I hope you get the idea. Regards, Wolfgang _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
