[sdiy] Lockout / DRM chips?

[cheater cheater]

I agree that the DRM is just one component of an otherwise healthy
business strategy.

Do you remember how much roughly the NXP chips added to your BOM?

> This seems to be the arc of most cryptographically enabled DRM.

I agree. I know about power monitoring, power glitching, and various
other hardware attacks.

One thing that I'm curious about is things like updating encryption,
in order to be able to repudiate compromised keys, eg from
manufacturers who have decided to start leaking them to companies who
shouldn't have them. This would at least require some sort of secure
vault with a machine of some sort inside, probably a VM.

Cheers,
D

On Thu, Sep 10, 2026 at 6:09 PM David Kantowitz <dkantowitz at gmail.com> wrote:
>
> The closest "on topic" experiences I have are with the contactless payment (and ID) cards.
>
> To read/write Mifare cards, we had to include the Philips (now NXP) reader chip in our equipment: even though our own DSP/FPGA generated the RF modulation signals and we had our own implementation of the on-air data protocol stack.
>
> All the Philips chip contained was their proprietary shared-secret encryption algorithm.
>
> Two things happened over time:
>   1. Researchers reverse engineered/discovered and published the exact proprietary cryptographic algorithm.
>   2. Various key recovery techniques were possible through either defects in the protocol implementation or techniques like power monitoring (which you can also think of as an implementation defect).
>
> This seems to be the arc of most cryptographically enabled DRM.
>
> The Philips chips were generally easy to use and the integration cost was more a one-time expense.  Still they added to the BOM cost.
>
> Even after the system was broken we continued to use them: it was the easiest way to vouch to our customers that our equipment was compatible with Mifare cards.  That compatibility was necessary because, by then, out customers had money sunk (ie. millions) into cards.
>
> Briefly off topic: that 10+ year experience taught me that DRM-like capabilities are small (nearly irrelevant) technical components in a broader commercial strategy ; figure out the strategy first and then use DRM as a temporary stepping stone in that strategy.
>
>
>
> On Thu, Sep 10, 2026 at 12:41 AM cheater cheater via Synth-diy <synth-diy at synth-diy.org> wrote:
>>
>> David, Mike,
>> Please start a separate thread, this isn't what this thread is about.
>>
>> Thanks.
>>
>> On Thu, Sep 10, 2026 at 8:58 AM David Huss via Synth-diy
>> <synth-diy at synth-diy.org> wrote:
>> >
>> > The idea to do some sort of multichannel modular via digital cables is not exactly new and not exactly something that isn't obvious.
>> >
>> > Technically such a thing is already done with ADAT/Toslink optical cables and many audio interfaces use it to allow users to add more I/O channels.
>> >
>> > So the main obvious question is why we haven't seen something like this widely used in the modular world?
>> >
>> > To me the answer is that the simplicity of the concept is unbeatable: Everything is just a voltage versus time, one signal per cable, what you see is what you get. All while being reliable, cheap to implement, cables are cheap, clocking is not an issue, it is conceptually clear, etc.
>> >
>> > The two useful applications of multi-channel cables I see are: (1) polyphonic modules where patching up 4+ cables is annoying and takes up valuable panel space and (2) breakout boxes for multichannel connections between racks (e.g. via Ethernet).
>> >
>> > Of course I could envision cool systems with multi-channel cables, but I am not sure it is really worth the extra complexity to make them digital. By that point one can ask, why not just run everything on a computer and make a patch-cable controller panel that just reads out the patch connections, knob positions etc and controls a big virtual modular.
>> >
>> > On September 9, 2026 11:44:34 PM UTC, Gordonjcp <gordonjcp at gjcp.net> wrote:
>> > >On Wed, Sep 09, 2026 at 07:31:21PM +0200, cheater cheater via Synth-diy wrote:
>> > >>
>> > >> So, there's good news and bad news. The bad news is that I can't go
>> > >> into specifics, but there are good reasons to expect a new modular
>> > >> format showing up sometime in the not extremely distant future.
>> > >
>> > >Good luck with that.
>> > >
>> > >How did you get one with your polyphonic modular idea with 24 channels of 24-bit 192kHz CV on a single 3.5mm jack?
>> > >
>> >
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