I heard about device which do an electric surge to burn some components. I also heard about magnetic device which set all the bytes to 0

Quantum computers won't magically break all encryption. There are some in-use encryption methods that won't be susceptible to quantum "attacks". Use one of those with a reasonable key size and they are completely unbreakable, assuming some flaw in the encryption algorithm isn't found. Of course no algorithm is immune from the risk of "oops, we didn't notice this weakness and now encryption is completely broken", so there is nothing to do about that

In general though why in the world are you carrying an encrypted drive with state secrets through a war zone? That's possibly the worst idea ever (unless you're writing a bad movie). As a result I'm finding it hard to understand the motivation here...

This sounds like a theoretical question. Nobody would carry such sensitive information in a hostile environment and rely on manual intervention to destroy it.

Strap it to a grenade ahead of time and throw it when needed. I can tell you that very few enemies would attempt to chase the storage device.

Data that can be harmful 50 years from now? Probably shouldn't leave whatever lab/secured govt building it belongs in.

@TeunVink You're technically correct - those people who carry such sensitive information into a hostile environment "do not exist". That body with the slightly greenish foam around the mouth? Just some hobo.

I for one have greater confidence in AES-256 surviving the next 50 years (even assuming quantum computers reach practicality) without a practical non-interactive attack, than in the reliability of any given physical device intended to irrevocably destroy a hard drive.

Wasn't there a DEFCON talk on this? Give me a second to find it... "DEF CON 23 - Zoz - And That's How I Lost My Other Eye...Explorations in Data Destruction" link: youtube.com/watch?v=-bpX8YvNg6Y

Can information ever be destroyed?

This question has gone off the rails with edits questioning the validity of Wikipedia, additional requirements, unrealistically "dangerous" data, and magical quantum computers that can break any encryption... If the data's that important, don't send it anywhere, tell your friends to come see it in your unobtanium armored lab run by perfectly loyal and alert Guardians of the Great Database or whoever you've trusted with this recipe to turn water into gasoline or whatever it is.

@GlenPierce I agree. The question almost seems like it's not being asked in good faith here, with every potential answer being rejected as "not good enough." If your hypothetical data is really that important that none of the below answers are acceptable, then why is it being moved at all? Have the people who need to see it come to you instead. The difficulties involved in getting them to your secure site and back home again are probably much less than those apparently required to keep this thing safe in motion.

@TheoreticalMinimum Yeah, and every answer is being systematically ruled insufficient due to new criteria that get added to your question each time a superficially viable solution is proposed. Why are we wasting time trying to answer your question if no answer given will suffice?

@TheoreticalMinimum This is a question about the real world (there just is no purely theoretical notion of "destroying information on a disk") - so it's completely meaningless without an assumed model of a real-world attacker's capabilities. As attacker capabilities approach infinity, all security vanishes, at least outside theoretical models.

Also, encryption isn't a solution to the problem itself - it's just a useful tool to drastically reduce the amount of data that has to be erased. It might still be interesting how to quickly physically disintegrate a small chip containing the key. In the real world, there just isn't any reason to try and destroy a whole hard drive instead (and risk some parts surviving).

Physical destruction of the storage medium - yes grenades, thermite, etc - will be your only route. Consider for instance, Apple's "secure" Trash erase routine which A) takes a long time and B) though it wipes the medium what - seven times - isn't guaranteed. Consider also how a generation ago, I forget which of the geek mags played Mythbuster with various methods "everyone knows" will wipe a drive… eg, electro-magnetic interference? They stuck some disk drives right next to electric train motors for a few hours and… nix!

This question sounds quite applicable to criminal activity.

i like the idea of printing barcode/qr keys (or one-time-pads if paranoid) on flashpaper or tissue paper than can be burned or swallowed quite quickly. A pre-populated connect 4 game gives you 36 bits of secrets that can be dumped on the floor (keep extra checkers with it to prevent ratio discovery).

As an aside (as I don't think it overly answers the question), the Science Museum in London had a GCHQ 'field office' sorts on display. Mounted to the door was a sledgehammer, pick axe etc in case of emergency.. Pictures can be seen here: thesun.co.uk/news/9428962/gchq-secret-office-shipping-contai‌​ner

A hard drive with a build in sanding wheel to sand all the magnetic material off the disks upon issuance of self-destruct command (basically it spins up, the sanding head comes in and just uses the 7200RPM+ to do the deed) would seem like what one would want. Of course, that can't be jury-rigged, but ideally one should be from a competent military force before going into a war zone. One might think of trying to induce a head crash, but I don't think it can 100% reliably be arranged to guarantee 100% removal of all magnetic material on the drive platters.

For improvise, I'd suggest a blowtorch directly to the platter, and if tools are not available, drop it HARD (from head height, if possible) on a solid surface while running until you hear a nasty sound coming, then leave it there to run the last few minutes so the head crash can do as much damage as possible and fuck the surface up as bad as it can. Better than nothing. Do it while it's open and get a ton of fingerprints and contamination and shit all over the disk before starting it up, just feel it as much as you can.

I want to point out that destroying the bulk material of the platter should not be necessary - aluminum is paramagnetic, so it is physically incapable of retaining persistent magnetization. Once you've got all the oxide layer off down to bare aluminum, nobody in the Universe will be able to recover anything (barring that time travel is actually possible).

Only reason I'm not posting this as an answer is because while I think it'll work, I'm not sure enough to fully endorse it and would want commentary.

@628426 "Can information ever be destroyed" This is one of the defining features of a black hole. Good luck carrying one around with you, though.

@The_Sympathizer Post an answer! Internet points are meaningless, and you get a 5:1 return on people who agree:disagree with you. Also, it allows better commentary.

SSD block erase is very fast. (and then use thermate?)

Worth noting is that when you crank up the threat model like this, little details start to matter more. Your options to erase a harddrive that's being hand carried in a warzone strapped to a Davy Crocket nuclear device are very different from your options for erasing a harddrive in the middle of a datacenter while you are on vacation in a foreign country!

Do you need ready access to the data as you go, or is it purely a transport job?

What level of innovation are you able to accept? "Can I destroy a hard drive with TNT?" and "Can I build hard drive platters around TNT?" are very different questions, and different again is "Can I use DNA data storage?". Are you only after technology that is empirically proven? commercially available? Cheap?

@Michael - Where's Clay Shirky Doesn't it (the information) just come out again when they (the black holes) radiate away?

@628426 Interesting. It looks like there isn't consensus (anymore). My information was circa 2002. Thanks for the tip!

Use write-only technology.