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Comment by amboar | Hacker News Reader

One of my favourite talks is Decapping Chips the Hard Way by Adam Laurie and Zac Franken: https://youtu.be/0Z4aF-qiziM

That was 8 years ago

how long before they will introduce special bad sectors on floppy disks, - sorry, wrong epoch, - special half-faulty components required for proper execution in chips to disable chip simulation/reverse engineering.

I’ll never forget the crack that I downloaded back in the days. It came with a PDF or image of a CD you were supposed to print, so you could drill through the burned CD at exactly the proper position. This was supposed to defeat the hardware dongle the software otherwise required. Can’t remember what software it was and never tried it to find out if this was a prank or actually worked, but I loved that as a kid :D

That sounds unlikely to work. I had a professor at the university who started his lecture on ECC by saying he always drilled a hole in all his CDs since he knew it would work anyway.

Or perhaps the ECC simply works well enough that there's no perceptible data loss for audio?

Wouldn't the CD explode soon after it got to speed? This happened plenty to discs that were just not made uniformly enough.

i think your leg was being pulled.

that said, one of the first copy protection schemes involved writing specific sectors to a magnetic disk with an invalid checksum. when the program would start, it would verify that reading those sectors would return an error, but if you used a regular disk copy program it would not copy the invalid sectors- either resulting in an aborted copy or a copy that would zero out the bad sectors on the target which would not produce the expected read errors on startup telling the program it had been copied.

There is no angle position sensor on the CD, and only one continuous track. This could work if you burned multisession CD, scratched at some specific radius of the first session, followed by coding that information into executable burned in the second session.

https://scarybeastsecurity.blogspot.com/2020/06/weak-bits-fl...

http://dmweb.free.fr/?q=node/210

http://dmweb.free.fr/?q=node/1429

https://scarybeastsecurity.blogspot.com/2020/07/turning-400-...

This one describes very similar floppy protection - encoding physical disk parameters in the executable per every individual disk. https://scarybeastsecurity.blogspot.com/2020/12/the-cleveres...

This effectively already exists. The Xbox One SOC apparently monitors its own voltage and shuts down / doesn't function if it falls out of spec [1] as part of a totally OTT suite of anti-engineer techniques.

As an aside, I hate all of this. If someone made an open console, I'd buy it in a second. I realise that's probably my computer running linux next to me, but still...

[1] https://www.youtube.com/watch?v=U7VwtOrwceo

Almost all microcontrollers have a feature like that - chiefly because at power-on the voltage rises gradually, and if it started running before there was a high enough voltage for it to run correctly you get a bunch of reliability issues.

> If someone made an open console,

Steam Deck?

What is OTT?

over the top

Yes, there are schemes that deliberately exploit difficult-to-reproduce manufacturing defects, for things like fingerprinting / making hard-to-clone things.

The general field is called PUF (physically uncloneable functions)

https://en.m.wikipedia.org/wiki/Physical_unclonable_function

The Z80 had deceptively-designed transistors designed to throw off reverse engineers: https://twitter.com/kenshirriff/status/1331425858268012545

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