[U-Boot] U-boot and GPLv3? (fwd)
Wolfgang Wegner
wolfgang at leila.ping.de
Fri Jul 3 17:51:16 CEST 2009
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
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