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I know about the USB devices that have a write protection switch that disables writing on the device side, are there devices that have a similar hardware switch that permanently erases the devices memory, or another method that can verifiably erase the data?

After watching this video I got the feeling that even snapping a micro SD card in half may not permanently erase the device, so I was looking for an alternative.

A switch or method to irreversibly destroy the memory could also partially answer this question but I worry that it would be harder to verify, since it is a trick you can only do once. Even devices that have a self destruct method of forgetting the devices encryption key require some trust from the user and the device to be plugged in at the time, the best answer would be a button that resets all the memory to 0.

daniel
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  • You could use thermite or acid to permanently delete the information. – anon May 29 '17 at 13:25
  • @anon but you couldn't get on a plane with it then. – daniel May 29 '17 at 13:26
  • a good charged condensator pack is maybe the way to go. Just fry it. – Serverfrog May 29 '17 at 14:25
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    this question sounds like a product feature overview - which makes it not a security question – schroeder May 29 '17 at 14:36
  • @Serverfrog I think zapping it could let the smoke escape without destroying the memory, if it were fused or the controller burnt before the memory then the data would still be recoverable with some work. – daniel May 29 '17 at 15:49
  • @daniel, as far as i know this is how some encrypted and self destroying usb Memory devices destroy themself. – Serverfrog May 29 '17 at 16:10
  • @Serverfrog OK I thought you meant just use a normal USB stick and then just fry it externally. I read briefly about the ironkey devices that will self destruct but cant find anything that would work with an unpowered device. – daniel May 29 '17 at 16:13
  • @schroeder this is a security question, these other questions also were about product features and they belong here: https://security.stackexchange.com/q/145664/8072 https://security.stackexchange.com/q/155132/8072 https://security.stackexchange.com/q/4248/8072 – daniel May 29 '17 at 16:17
  • @daniel I disagree with your examples: they are looking for techniques, you are looking for a literal button on a product – schroeder May 29 '17 at 18:01
  • If you really want high-security, you should probably be looking at something related to smartcards rather than FLASH drives. High security smartcards are made to self-destruct the data if they are probed. – Julian Knight May 29 '17 at 19:11
  • @schroeder alright I've tried to fix up the question – daniel May 30 '17 at 06:26
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    a raspberry pi with a ramdisk and usb host would allow destruction via removing power – dandavis May 30 '17 at 18:58
  • Carrying a fully encrypted USB-Thumbdrive, assuming decent encryption, would be non distinguashable from a thumbdrive overwritten with random data (so it will be "erased" in advance). – Jonas Köritz May 31 '17 at 06:56
  • @JonasKöritz also assuming the key is kept secret and its not brute forced. I'm assuming this device would be stolen away forever after the button was pressed. – daniel May 31 '17 at 07:13
  • Completely unpowered would be illogical, but it's not farfetched to think if you had an encrypted drive with a battery and a killswitch, activating the killswitch would erase the encrypted volume's header information and render the entire volume useless (LUKS is supposed to work like this). I wouldn't trust it on multiple levels, but it's not inconceivable. – Ivan Jun 05 '17 at 15:54
  • The point of a device like this could be for passing through customs, so instead of saying "I don't have the key to this data" you could say "look there is no data" after you let go of the dead mans switch. https://www.wired.com/2017/02/guide-getting-past-customs-digital-privacy-intact/ – daniel Jun 07 '17 at 20:36
  • There is something called bulk erase flash memory that might be what I'm looking for, [link to a 1 megabyte IC][1]. [1]: http://www.onsemi.com/PowerSolutions/product.do?id=CAT28F010 – daniel Jun 08 '17 at 21:35
  • but the 1 MB IC might take 10 seconds to erase, 1 GB chip might take something like 8 minutes, so not my solution – daniel Jun 08 '17 at 21:47

2 Answers2

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Tamper-resistant devices, like the PIN pads you see at cash registers, often store their keys in a CMOS chip that requires a battery to keep the storage refreshed. If the circuit detects tampering (someone removes a screw, or drills the PCB, or breaks a tripwire cutting into the epoxy, or trips whatever other sensors the manufacturer included), the battery power is cut and the memory is drained. The chips used for this are often in a BGA package, making it that much more difficult to access the interior pins. Adding a push-button kill switch into the tamper detection circuit would not be a problem, if one was needed.

The Mooltipass Mini offers securely encrypted password storage in a pocket-sized tamper resistant package. Three wrong guesses at the PIN and the master key is wiped. But it doesn't have a kill switch, and it acts as a keyboard, not a mass storage device.

I have never seen a tamper-resistant mass storage device of the kind you seek. That doesn't mean they don't exist; just that if they do, they have very poor marketing.

John Deters
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  • This is useful, CMOS SRAM would take a little battery, it would forget what its holding quickly when disconnected (seconds or minutes at room temperature), and it looks like you can get 8 megabytes on a chip nowadays. – daniel Jun 07 '17 at 20:04
  • @daniel, if you are interested in building your own solution, there are many extremely tiny Linux boards available now. Pick one, mount a MicroSD card, load up a mass storage USB emulator, and add an encrypting file system. Add a push button as a kill switch to wipe the on-board key, and you're set. (Designing and implementing tamper resistant packaging is left as an exercise to the reader.) – John Deters Jun 07 '17 at 22:00
  • Deleting a key leaves me the problem of explaining a large encrypted file I cant open, or possibly having NOBUS open it later. so I'm looking for an instant or quick way of zeroing a large volume without damaging the memory. – daniel Jun 07 '17 at 22:13
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There is no inexpensive commercially available device like this. The only devices that would provide unpowered data destruction would either be hazardous or of extremely low data density (128 bits).

this.josh
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  • as dandavis said DRAM in a raspberry pi would lose its data quickly when power is removed. But that doesn't look like a commercial product anymore, its carrying around a mini computer in your pocket. – daniel May 31 '17 at 06:41
  • There are lots of potential answers, but given the implied criteria of replacing a micro SD card, there are no solutions of appropriate size, capacity, and cost. – this.josh May 31 '17 at 06:46
  • 128-bits is enough if the USB has hardware encryption and the key is placed in that 128-bit sector. – Lie Ryan Jun 05 '17 at 03:11