[Arm-netbook] HDMI Player Stick as DRM-free Merch Alternative

Richard Wilbur richard.wilbur at gmail.com
Tue Jul 24 02:46:36 BST 2018

> On Jul 22, 2018, at 15:11, Jean Flamelle <eaterjolly at gmail.com> wrote:
> A monofunction PCB that when power is supplied from the HDMI,
> generates a private key signature, displays it as a QR code for a few
> moments, then plays whatever video is stored on nand.
> The QR code confirms the legitimacy or official-ness of the copy.

This sounds similar, in concept at least, to something like a GPG signature over the presentation content.  The processing to calculate the signature over a feature-length high-definition video (Blueray movie ~15-25GB[max single layer])[1] to verify authenticity is significant.  I would recommend implementing the algorithm in FPGA (eventually ASIC?) to speed the calculation.  I don't know what calculation time would be acceptable.  We can probably buy some user patience with a real, honest, linear-response progress bar and possibly a countdown timer.  Let's say we have NAND read rates that allow us to pull 1GB/s into the signature processor and we can process data as fast as it arrives.  That would give us 1s of calculation time for every 1GB of content or 15-25 seconds to calculate the QR code.

Samsung has a 32GB chip with a high-speed serial interface capable of 880MB/s in sequential reads.[2]  That's ~88% of the speed we talked about above.  (25GB transfer in 28.4s)  And it is in mass production!

The size sounds good, too:  11.5x13x1.2mm

(I had some time to burn while riding around with my family to different appointments and waiting while the girls were in lessons.)


[1]  https://en.m.wikipedia.org/wiki/Blu-ray
[2]  https://www.samsung.com/semiconductor/estorage/eufs/

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