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I'm Building a Self-Destructing USB Drive Part 2

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Re: I'm Building a Self-Destructing USB Drive Part 2

#21

Post by dheera »

2OEH8eoCRo0 wrote: post #15
yellow_lead wrote: post #2

Does this actually prevent forensics from finding any data?

No. If you do this as part of a legal search and they catch on you're now in a lot more trouble and you've caught their attention.

It would probably be better if the device self-destructed automatically if some kind of dead-man switch signal isn't given. Like having to press a button at least once a day or maintain reception at least once a day with an implant inside the owner's body; else it self-destructs.

That way you aren't doing anything, it's their act of arresting you or sneezing your device that causes the destruction. If they want to keep the evidence they have no choice but to keep the device in your possession.

Re: I'm Building a Self-Destructing USB Drive Part 2

#22

Post by Kirby64 »

system2 wrote: post #9
lofaszvanitt wrote: post #5

Earlier quoted context omitted.

Not at all.

Why not? If the data is zeroed, there wouldn't be anything to find by forensics.

You're not zeroing the data, you're just burning up the flash memory in some way... which is not necessarily going to reliably damage the actual contents of the data, most likely it'll probably just damage some built-in voltage regulator or IO. For a truly determined adversary, you could pull the flash chip and read the contents directly. It's much more difficult, but theoretically possible if the information is valuable enough.

Re: I'm Building a Self-Destructing USB Drive Part 2

#23

Post by 2OEH8eoCRo0 »

dheera wrote: post #21
2OEH8eoCRo0 wrote: post #15

Earlier quoted context omitted.

No. If you do this as part of a legal search and they catch on you're now in a lot more trouble and you've caught their attention.

It would probably be better if the device self-destructed automatically if some kind of dead-man switch signal isn't given. Like having to press a button at least once a day or maintain reception at least once a day with an implant inside the owner's body; else it self-destructs. That way you aren't doing anything, it's their act of arresting you or sneezing your device that causes the destruction. If they want to ke…

I wouldn't risk it. Don't break the law in the first place. Comply with legal requests. If you're a journalist be careful!

Re: I'm Building a Self-Destructing USB Drive Part 2

#24

Post by wizofaus »

dheera wrote: post #21
2OEH8eoCRo0 wrote: post #15

Earlier quoted context omitted.

No. If you do this as part of a legal search and they catch on you're now in a lot more trouble and you've caught their attention.

It would probably be better if the device self-destructed automatically if some kind of dead-man switch signal isn't given. Like having to press a button at least once a day or maintain reception at least once a day with an implant inside the owner's body; else it self-destructs. That way you aren't doing anything, it's their act of arresting you or sneezing your device that causes the destruction. If they want to ke…

> It would probably be better if the device self-destructed automatically if some kind of dead-man switch signal isn't given

How is that not what's being described here? The dead-man switch signal is to moisten your fingers before plugging it in.

Re: I'm Building a Self-Destructing USB Drive Part 2

#25

Post by amelius »

squarefoot wrote: post #8

I don't like how it's engineered: the uC is completely overkill as the high voltage could be generated by a single transistor switcher that charges a capacitor, not unlike those "Joule thief" circuits used to light higher voltage leds with small batteries. The mosfet would then just switch that voltage, which could well be tens of volts or more. However, the working principle assumes the user's skin would be normally…

I don't like the initial assumptions: that a cop would never have wet fingers, or that you'd never miss the contacts or have partially dry fingers when plugging it in.

Re: I'm Building a Self-Destructing USB Drive Part 2

#26

Post by nibbleshifter »

2OEH8eoCRo0 wrote: post #23
dheera wrote: post #21

Earlier quoted context omitted.

It would probably be better if the device self-destructed automatically if some kind of dead-man switch signal isn't given. Like having to press a button at least once a day or maintain reception at least once a day with an implant inside the owner's body; else it self-destructs. That way you aren't doing anything, it's their act of arresting you or sneezing your device that causes the destruction. If they want to ke…

I wouldn't risk it. Don't break the law in the first place. Comply with legal requests. If you're a journalist be careful!

No post body was provided.

Re: I'm Building a Self-Destructing USB Drive Part 2

#27

Post by morcheeba »

pjerem wrote: post #18
imglorp wrote: post #12

Earlier quoted context omitted.

You could use a scheme kind of like how port-knocking works. For example, plugging in directly causes self-destruct, but plug and unplugging twice in 5 seconds will be the "okay it's me" signal. This could be implemented by writing a timestamp file on wakeup.

> This could be implemented by writing a timestamp file on wakeup. You’d need to embed a clock and an energy source to keep the clock going.

A 150uF capacitor should keep the microcontroller running for about 5 seconds without power; it could keep time. 7.3mm x 4.3mm x 2.9mm

Re: I'm Building a Self-Destructing USB Drive Part 2

#28

Post by mrguyorama »

dheera wrote: post #21
2OEH8eoCRo0 wrote: post #15

Earlier quoted context omitted.

No. If you do this as part of a legal search and they catch on you're now in a lot more trouble and you've caught their attention.

It would probably be better if the device self-destructed automatically if some kind of dead-man switch signal isn't given. Like having to press a button at least once a day or maintain reception at least once a day with an implant inside the owner's body; else it self-destructs. That way you aren't doing anything, it's their act of arresting you or sneezing your device that causes the destruction. If they want to ke…

Unless there is ample precedent or case law showing that this kind of rules-lawyering is acceptable, always assume judges would frown upon obvious attempts to subvert the intent of law by using the wording of the law.

Unless of course you are a big company, in which case that seems to be the expectation.

So the real advice here is just to be a very important person.

Re: I'm Building a Self-Destructing USB Drive Part 2

#29

Post by [deleted] »

dheera wrote: post #21
2OEH8eoCRo0 wrote: post #15

Earlier quoted context omitted.

No. If you do this as part of a legal search and they catch on you're now in a lot more trouble and you've caught their attention.

It would probably be better if the device self-destructed automatically if some kind of dead-man switch signal isn't given. Like having to press a button at least once a day or maintain reception at least once a day with an implant inside the owner's body; else it self-destructs. That way you aren't doing anything, it's their act of arresting you or sneezing your device that causes the destruction. If they want to ke…

[deleted]
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