FC: Hollywood wants to plug "analog hole," regulate A-D

[Neil Johnson]

On Sunday 02 June 2002 08:24 pm, Joseph Ashwood wrote:
>>
> The MPAA has not asked that all ADCs be forced to comply, only that those
> in a position to be used for video/audio be controlled by a cop-chip. While
> the initial concept for this is certainly to bloat the ADC to include the
> watermark detection on chip, there are alternatives, and at least one that
> is much simpler to create, as well as more benficial for most involved
> (although not for the MPAA). Since I'm writing this in text I cannot supply
> a wonderful diagram, but I will attempt anyway. The idea looks somewhat
> like this:
>
> analog source ------>ADC------>CopGate----->digital
>
> Where the ADC is the same ADC that many of us have seen in undergrad
> electrical engineering, or any suitable replacement. The CopGate is the new
> part, and will not be normally as much of a commodity as the ADC. The
> purpose of the CopGate is to search for watermarks, and if found, disable
> the bus that the information is flowing across, this bus disabling is again
> something that is commonly seen in undergrad EE courses, the complexity is
> in the watermark detection itself.
>
> The simplest design for the copgate looks somewhat like this (again bad
> diagram):
>
> in----|---------------buffergates----out
>         ----CopChip-----|
>
> Where the buffer gates are simply standard buffer gates.
>
> This overall design is beneficial for the manufacturer because the ADC does
> not require redesign, and may already include the buffergates. In the event
> that the buffer needs to be offchip the gate design is well understood and
> commodity parts are already available that are suitable. For the consumer
> there are two advantages to this design; 1) the device will be cheaper, 2)
> the CopChip can be disabled easily. In fact disabling the CopChip can be
> done by simply removing the chip itself, and tying the output bit to either
> PWR or GND. As an added bonus for manufacturing this leaves only a very
> small deviation in the production lines for inside and outside the US. This
> seems to be a reasonable way to design to fit the requirements, without
> allowing for software disablement (since it is purely hardware).
>             Joe


Bzzzzztttt! Wrong Answer !

How do you prevent some  hacker/pirate (digital rights freedom fighter) from 
disabling the "CopGate" (by either removing the CopChip, finding a way to 
bypass it, or figure out how to make it think it's in, "Government Snoop" 
mode ) ?

Then the watermark can be removed.

Remember it only requires ONE high-quality non-watermarked analog to digital 
copy to make it on the net and it's all over.


-- 
Neil Johnson, N0SFH
http://www.iowatelecom.net/~njohnsn
http://www.njohnsn.com/
PGP key available on request.