which chemical to deactivate microchips?

Hi, I'm making a cryptex, such a thing like in the Da Vinci Code, and I'm going to make an Instructable of it later. But I'm going to hold USB-sticks in it instead of a piece of paper. That's a little more modern nowadays people lose a lot of usb sticks with secret important information so I'll use a cryptex for it. The crpytex like it was invented by Da Vinci contained a paper, which was rolled around a tube with vinegar in it. If someone decided to just smash the cryptex, the tube breaks and the vinegar would destroy the ink on the paper, making it unreadable. I don't think that works good in real but I don't think it will deactivate a usb stick either. So I want something else in the tube that DOES eat the chip. So I'll remove the outside wrapping of the USB-stick. What fluid can I use?

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klee27x8 years ago
Forget fluids. Strong acid might be the only way to permanently destoy a chip with fluid. But even that would take a long time, and it would also be very bad for the guy who broke it... and the carpet. The only other fluid I can think of is maybe a very fast acting foaming 2-part epoxy with ground up copper/silver/graphite particles to make it highly conductive. Again, that would be pretty messy. I suggest you rig up a booby trap, so when the tube breaks the USB stick gets zapped with high voltage.
klee27x klee27x8 years ago
.. or maybe just a 3V watch battery, applied in the wrong direction.
I have not tested it, but flash drives seem to be quite durable.
merijnvw (author)  klee27x8 years ago
thanks!
legionlabs7 years ago
You'd have to sacrifice a USB stick to test it, but highly concentrated salt water would probably damage the ICs *if they were receiving power*. I once lost a USB device during a violent storm this way.

Alternatively, cut several of the traces on the USB stick and then manually repair them with a thin layer of conductive epoxy (not power supply traces!). Exposure to a strong solvent (acetone, xylene) may undo the repair, and most people will not know how to fix this.

Overall I agree with klee27x, use electricity, not chemistry! My only additional suggestion would be to consider using high(er) current, not high voltage... I imagine 10v providing up to 1A would make a USB stick smoke visibly and without the inconvenience of transformers or voltage doublers.
Kaiouss8 years ago
As everyone else has been saying, there probably isn't much in the way of non-hazardous chemicals. That being said, you might try putting a very, very, very, very (I can't stress that enough) small amount of thermite between the edges of the chip and the pcb and have a small piece of magnesium attached to that. At that point, it's up to you how the magnesium gets lit, but thermite would irreparably destroy the chip and the board. If it burns for so long that it burns through the drive, then you'd have problems.
zimmemic258 years ago
open the case of the flash drive, add a metal bar under the chip. then build the cryptex in a way that when its opened, only the usb plug is accessible. but if its broken, the metal lever would be pushed and would break the chip off the PCB. then some of the chip's pins would be ripped out of the chip's plastic casing, and nobody can re-solder it in place to repair the usb drive
PKTraceur8 years ago
What about using galinstan? That is a conductive liquid metal, however it is not toxic. That might short circuit it. Or, you could take some battery acid from an old carbattery, contain it in a glass vial, and walla, instant melt... Or, you could "soak" aluminium in galinstan, and have a second vial filled with water. This "soaked" alumnium will bubble hydrogen, a very flammable gas. (Im sure you will know most of this.) In complimenting to that, you could have a third vial filled with Dran-O, and when Dran-O comeis contact with the aqueos solution that the soaked aluminium and water made, it will instantly precipitate the galinstan, and metal will appea EVERYWHERE on the chip.
I suggest using a securely encrypted flash drive whose chip cannot be removed without destroying it. This one, for example.

Then soak a piece of tissue paper in baking soda and dry it. Use pen to write the passphrase of the flash drive. Vinegar will not destroy the paper any more than plain water will, but the bubbling action of the baking soda and vinegar reaction should help to tear the wet paper and spread the ink.

Or you could just memorize the passphrase, but where's the fun in that?