On SSD's you shouldn't use this method at all, that's kinda what I imply at the end of this short. ;) Use a secure erase tool like blkdiscard.

@@ex-itguy if you're going to use this on any drive, the speed of the operation can be improved if you can the highest number of bytes the drive size is divisible by that is LOWER than the square root of its total size, a multiple of 4096, and smaller than the drive's cache. And set bs=thatNumber as an option in dd. I'll look into blkdiscard, though. Thanks for the tip.

​@@seancondon5572 that's some valuable information right there! I've pinned your original reply so people can find this one easily. 😊

indirectly this is the answer why people smash their harddrives instead. if you have an old drive that you don't have any use for, why would you take the time to write several passes of random data, when you can destroy the platters instead. though, smashing them only works well for glass platters.

i don't think people understand this for some reason but 7 passes is NOWHERE NEAR enough digital shredding to stop the NSA or other state actor. magnetic storage media like hard drives contains permanent, unremovable traces of everything it has ever stored. Zeroing an SSD works especially if the SSD correctly supports ATA Secure Erase. The only way to perfectly zero a _hard drive_ is to _physically_ shred it.

@@tacokoneko And to add up, don't just smash it, use a strong magnet and degauss each of the plates while it's still on power. It's a good way to do this if you don't want anyone to find your HDD shredded into pieces, better to look like it's fully working than not, as that can bring more attention to your case if there are any complains about your storage somehow. After all, the way 3 letter agencies destroy hard drive data is by using a really strong degaussing machine to rip apart all its magnetic structure on the drive.

The joke is 1 pass is enough. I cannot believe there are still existing standards with 3 or 7 or 35 passes in order to not degauss or destroy a drive physically. Force electron microscopy was only a thing for a brief moment back in the day of up to 8GB IDE drives.

@@jackburton6330 I don't really agree with that one pass idea, in a more serious manner, as it was already confirmed in some cases, that one pass is not enough to "be assure that the old data cannot be compromised" but yet, only one pass can be ideal for an everyday computer user that just wants to be reassure that normal techniques to compromised old hard drive data cannot be really executed on his HDD. Though, I can disagree with something, the method I was talking about is still being used nowadays, and it's still known to be one of the best methods to get rid of data without physically dismantling a SATA drive. Nonetheless, we can all agree with something, that the method I've described is only used by agencies and paranoid people that think the opps are following them, so we can't really take this seriously at all, it's just a curious fact about fully erasing data on a HDD.

That's quite important, yeah 😋

Well, you can always plug ONLY this harddrive and a spare boot flashstick to load the system.

@@ex-itguyhow do you format an SSD?

Classic Disk Destroyer moment

​@@mangodude-nq6su I'm using Linux for about a year now, and I picked the wrong device about 2 weeks ago haha. Don't worry, I just destroyed my arch linux portable disk, and later that day I flashed it again. No data was hurt in this process.

Oh there's a backup in the cloud, but no-one can copy them from this drive hahaha

As you say sir, my math homework must be safe

@@Nagytika whos gonna tell him

@@JasperFoxo I'm pretty sure he knows...he might have seen more "homework" than any of us through his profession ^^"

@@Nagytika fair

I see what you did there 😉

Huh... I just random rewrite the whole device, & then use it to store all the movies & TV shows & music I download. To each their own.

Didn't know that! Should try it sometimes.

@@ex-itguy Gotta use a command line to get hd_parm to do it, IIRC. And, essentially it just tells you how long to wait for it to do it.

That's what I did before giving 5 old drives away to a friend.

Provided that you trust the controller to actually erase the medium and not just pretend for the greens ;>

@@ex-itguy I would recommend it as on modern drives, bad blocks are remapped with reserve blocks to replace them. After a block is remapped, the OS can no longer access the block in order to overwrite the data. That is unless tools are used to remap the bad block so it can be accessed again.

Yup. _Any_ encoding becomes non-recoverable, if a few bits are altered _and_ you don't know what order anything was stored in.

if a single full disk write on your ssd wears out your flash cells then your ssd is already in a state of not being useful in the future anyways

How do you do this on linux?

@@seriouslyWeird You _never_ write to the full "disk" on flash cells; the extra space is used for wear leveling & the allocation will fail if you try to fill every sector. Best case, it'll soft-brick so bad you need a firmware writer to fix it. Also, the cells of an SSD can't handle nearly as many rewrites as a hard drive platter can; the built-in Secure Erase functions are as good as you're going to get without wearing out the chip.

In theory, you're right. That's why I mention you could switch to /dev/urandom in the video.

Has this ever been done in practice though? Meaning for the average user is it that important? Of course if you have stuff that's very sensitive always best to be safe

​@@CorrosiveCitrusthat's exactly what I'm saying. If your data could be worth paying someone a lot to get... you might want to consider multiple takes. For the average user. Nah.

Oh noes, responded with the wrong account 😂

@@CorrosiveCitrus I recommend watching the "Nothing to hide" documentary.

And is a waste of resources, because a new drive has to be manufactured instead of just reusing an old one.

If someone is smashing a drive with a hammer it's because it is going into the trash. If it was actually still useful they would probably just reformat and use it in something else. This may come as a shock to you, but no one else wants your e-waste.

@@aviandragon1390 what about personal use, and recycling?

@@BlenderDestruction you left him stumped lol you are right

@BlenderDestruction Hmm, your username gives me an idea of an even better way than using a hammer.

Yeah they've done studies showing that even after several rewrite passes, data can still be recovered with magnetic forensics. This is why government agencies etc require drive smashing, however if the data was encrypted to start with then its not a concern, unless somehow AES-256 is bypassed someday.

is encryption really not an issue, considering the upcoming era of quantum computing? is your encryption algorithm quantum proof? how do you know there won't be a flaw found in the specific encryption algorithm or implementation in the future?

@@seriouslyWeird it's a fair point, but for me that risk is very low by the time quantum computing gets in the hands of anyone who would come across my old drives... The data on there would be very outdated and not so useful to them, which would likely mean they wouldn't even bother The risk is much higher that my collected network traffic (and many others) is breached, for which I don't have a solution for

@@seriouslyWeird theoretically, but quantum computers are still a ways away, with only high 2digit qbits at best and still very noisy outputs at the moment. It's also not that trivial to program a quantum computer even for something it would be good at like decryption by force

@@sage5296 of course it's years away, but articles state that within a decade we will see first useful quantum computers and the necessity of post-quantum encryption will be very relevant soon

How is it faster the command he said goes as fast as the write speed of the drive and does it thoroughly (accept bad sectors which nothing can over write on them anyway besides physical destruction)

@@samanthagriffinv2.08 I measured it in a Celeron dual core at the time, so I might have been CPU bound. Either that or it has to do with gathering entropy for the cryptographically secure random number generator.

The difference was very significant, I saved hours on that

​@@samanthagriffinv2.08It's possible it doesn't read from those dev files or isn't particularly careful (parody bits and checks might be done before dd is sent over)

​@@rya3190"parody bits" is the best typo I've seen all week. Freaking parody errors, man.

From dust it came, to dust to shall return

So you can lose the data when you old drives fail? No thanks.

@@Fooney1 does your entire pc run off cloud?

@@bby256 What does that have to do with old hard drives not being good?

@@Fooney1 what if your computers drive fail then? There are ways you can check hard drive health and buy new if you need

@@bby256 If my drives fail it's a problem which is why I don't use old drives. The drive heath will only show a problem before failure if you are lucky. Would you buy a car will 300k miles on it just because it has no check engine light on?

Sure, if that's what you like. This one's mostly aimed at people wanting to sell their old systems but don't want anyone to get their old files.

​@@ex-itguySo selfish! Share those embarrassing photos with the world!

Yay, someone else who also uses LUKS

Luks and lvm user here

You are not overwriting every bit in 30 mins. What you meant to say is you have been lazy and it hasn't hurt you yet.

​@@Fooney1With encryption, there is no need whatsoever to overwrite every bit. Damaged encryption is hard to reconstruct even when you know what it is. That's actually why I _don't_ encrypt my drives. 🤷 In the rare event of failure, it's nice for the data to be recoverable.

This old myth again, no one has ever been able to recover even a kilobyte of data from a properly 0'd out drive. The idea that we could read slight magnetic fluctuations with enough resolution to probabilistically recontsruct even one file is extremely unlikely. You know what is likely though? The drive you foolishly smashed instead of formatting has large swaths of the platter recoverable by a well-funded attacker, since unlike your magnetic fluctuations theory they don't have to operate at nano-meter scale

​@@borisyeltsin6606 I don't actually know if that's true but even if it is, if I'm gonna write the disk over either way, I'll take random over zeros on the off chance such theoretical recovery becomes reality

​@@QuickNETTechthe problem of using urandom is that you need a sizable entropy for it to be more effective....

​@@ChimeraX0401 what does entropy has to do with this? if i wrote 0x00, 0x01 and 0x02 in a repeating sequence to the drive, it's probably just as effective than writing random data, even though this sequence is preditable and reproduceable.

@FunctionGermany But then you are not getting the advantages of urandom against zeroing. As you said, that is predictable, which is what needs to be avoided. It has the same problem as zeroing. You need entropy.

I don't know of anyone doing it yet, but you can absolutely build a board to digitize arbitrary streams in an aalog mode, just like has been done for floppy drives with e.g. GreaseWeasel.

People commonly replace a drive controller with a similar drive controller to repair it.

i mean the platters on their own aren't readable yea, but it's not that difficult to find a compatible one if you know the dimensions

Yeah... if all your sensitive data fits in the bad sectors of a drive I think it's about time you smashed it haha

Good to know

Well a friend of mine wanted to sell his old server (video on the channel) and I needed to clear that to make sure no-one can get to his client's files. Nothing sketchy about that. ;)

A magnet will wipe out the physical ones and zeros on the magnetic disk. Not all of these are for data storage. Some act as guides to tell the read/write head where it is/how to read the drive etc. Using a magnet will brick the drive. If you're gonna use a magnet, you might as well use a hammer too.

modern hard drives are extremely resilient to magnets

@@tennicktenstyl Hard drives still are, always were, and always will be, incredibly vulnerable to magnets. It's called "magnetic storage" for a reason. You might be thinking of SSDs, which don't have the same vulnerability. But if you think for a second that your data is surviving a magnet stuck onto your hard drive, then you're going to be very disappointed. If the read-write head is capable of overwriting bits, then a magnet a hundred times it's size can certainly brick a hard drive.

@@n00bxl71 they aren't. Watch some tests on youtube, the magnet would need to be huge to do any damage.

Two words "hdd degausser" that actually does what you think a wimpy normal magnet would do.

Exactly, so if you have anything that you really don't want anyone to find, you should do multiple passes. On SSD's you can use blkdiscard.

and SMR HDD's - just exist. Space between the tracks - not only it doesnt exist, but tracks are overlapping.

Is there any evidence that such labs can read once-overwritten data on any modern (say 2010 and forward) HDDs? My understanding is that it WAS possible until areal density got past a certain point.

@@ex-itguy Multiple passes and smashing if you're worried about the fucking government

That's what I understand as well. Really no reason to destroy your disks.

Haha, process finished as soon as computer stops talking. 😄

Do iiiiiiiiiiiit 😂

... just read the wiki entry of arch linux about wiping ssd... it's way easier and take 3min instead of multiple hour. I know because i dumpster dive and reuse for my NAS the hdd and ssd i find. badblocks -wsv is a must then do a smart self test. The badblocks command above can be used instead of wiping the drive like the video say.

Microwave it for a couple of secs

@@mx676 please help my house burned down

@@mx676 not sure of that will really get rid of the data. It will burn the logic board, but you can replace/fix that. ;-)

That's weird. I use an old harddisk platter with bent edges to increase the surface area of my motorcycle's kickstand when I park in grass. I know others who do the same.

@@ex-itguy "Reduce, Reuse, Recycle" in action. :)

Indeed haha

I haven't tested that on a harddrive. Tbh I just didn't know harddrives had that functionality before some of you pointed it out to me. I did know that was the case for SSD's.

That's mostly the issue for SSD's, but you've got a point.

I'd love to see you try after two or three passes.

@@ex-itguy I wouldn't be able to, but I've worked directly with people in high level data forensics, and they can pull some insane shenanigans to get data off of broken, dead, and overwritten drives.

I wanted something that is always there, no need to install anything. But it's a good option nonetheless.

I know, and I think it's kinda stupid

@@ex-itguy But the data is lost eventually, isn't it?

Yes, and the drive as well. That's the stupid part if you ask me. ;-)

True. That rest can be a problem for some but its not really an issue.

If you set up encryption first, getting rid of the key is as roughly as good as destroying the data (eg, print most of the key on edible wafer, store carefully, then eat wafer once done)

​@@Aera223 Just to clarify for others, silicon wafers are not edible. Speaking from experience.

@@KelvinShadewing lol... was thinking biscuit wafers... but didn't clarify.

🤣

Uzaiyaro-- The old HD utility "Spinrite" is ideal for checking the whole media surface for latent bad blocks. As you pointed out, the HD could have an unacceptable number (possibly an OEM fault), but you never would know until running Spinrite. This utility test-writes, then reads multiple times, in an attempt to restore blocks reliably

So what would you suggest? Destroying (the data on) the disk is the whole point of this action. Edit: missed the second part of your comment haha

​@@ex-itguytho come to think of it, I don't get rid of drives, I keep them... And for older PCs, I also keep them, especially if they work... running a server on an old laptop is cool

I don't. I'd rather put my stuff on one bigger drive than having stuff scattered among a bunch of old smaller ones haha

@@ex-itguy Very bad idea. If that one drive damages, you loose everything. If one of several smaller drives gets damaged, you lose only its content, while all the rest is still fine. Diversify your storage.

Nah, I'm fine, I have backu... oh crap! 😅

This is obviously not about corrupted drives ;)

Could you point me to a video of someone recovering data from an overwritten disk? I don't believe it's possible, after a few passes with random data in-between.

Bzzzzzzt *poof* 😆

Why shred it after 7 passes? What's the point of clearing it then?

@@ex-itguy more to the point why not, new techniques are always coming out. if you need to use the drive after then yeah just 7 but if it`s critical i would consider that drive needs to represent something more like a bag of dust lol, but yeah 7 passes should be fine

I meant: why bother wiping it if you're going to shed it anyway?

@@ex-itguy yeah just shredding would be fine. my thinking comes from the fact that its not technically impossible to reconstruct a drive even with extreme damage

If you'd rather add the the growing pile of e-waste than wait for 20-30 minutes for this action to complete, then by all means do so.

Then this drive will be unable to be reused by anyone else, yourself included.

@@bonbonpony That was the whole purpose, If I I understood it correctly. There's an old but working HDD that I don't trust anymore and want to throw it, but it contains my personal information.

People are frantic about it, that's why. I have yet to see anyone recover data from a drive that has been overwritten a few times.

Older disks use magnetization which isn’t as simple as totally 0 or totally 1. Overwriting it can leave small traces of how it was magnetized before, so doing it multiple times is necessary.

Tbh, I wouldn't do multiple passes. On more modern drives the density is so high that just overwriting the data once is perfectly fine. And even then, on older drives, you need specialised tools to get the data back. Your standard unformat and undelete tools won't find anything. I disagree with you on your last point. I see a lot of people telling others to thrash old drives to make sure no-one can get your data. On the other hand, it's better for people like me getting dysfunctional systems for free or very cheap that the previous owner probably could get (more) money for fully functional 😆

For my linux system, if I'm done with it, I can just forget (or pretend to forget) the passphrase, and the data will require too much effort for most to recover (it takes a few seconds to unlock even with the right passphrase)... A quick format on the encrypted drive and a few files plopped in... and LUKS is going to take wayyy too many centuries to recover

nowadays all computers are connected to the net, 99% don't know how to secure their data, it is worse than the disposal problem discussed here. ideally every file needs to retain a copy history and an access log so we can detect malicious activity

On modern drives (12 y/o 500gb drivers I just did, I consider "modern") that's not true. Data on these drives are so dense that after a few passes, nothing will be recoverable.

A drive full of memes is always a good idea haha

Well if the feds are already knocking you're a tad too late haha

​@@ex-itguyimo that's the only time, a hammer would be the better option, in fact, hdds can come with a self destruct option that scrapes the magnetic coating before recovery

That's more work, but would probably be fine as well. The idea is to overwrite everything with new data.

No, overwrite it with random. If there's a repeating pattern, it can be used by the recovery team, because it works pretty much the same way as overwriting with zeros (a constant offset, just every nth byte has a different constant).

If you only delete useful files and then make multiple copies of the same picture file, you might have so called "slack space" that can contain data from your old files, as well as filesystem structures on the disk containing metadata. Even if you recreated the filesystem, you'd still have the slack space issue.

​@@EmilFryou're right. I almost forgot about that! The horror of tiny files taking up a lot of space on my FAT16 formatted 1GB drive...

Can't argue with that!

You do you!

You don't have to wait it out. ;)

You can't without special equipment. Companies that can help you with that aren't cheap. Also: that's why I suggested to do multiple passes and maybe switch to /dev/urandom of you are really anxious about it. Especially when using random data a recovery service will have a hard time figuring out if fluctuations are old data or just the new random garbage.

Except for the blocks that the ssd keeps hidden to the OS. Better use a secure erase tool like blkdiscard.

Happy to be mid tier 😂

I'd love to! 😄

I'm using a platter with bent edges to throw under my motorcycle kickstand on soft surfaces haha

Sure, in that case you're absolutely right! This is mostly aimed at people thrashing drives that could get a second life perfectly fine.

Interesting. But it seems you need specialised tools for that isn't it?

@@ex-itguy yes true, but if you're doing a few 100 you could probably pay for one with the electric and time saved. We use a verity systems one, great tool but my god it's noisy. The drives are totally knackered after 4 seconds a side burst. Extreme magnetic fields created.

If you do it that often, yes. But will the drives still be usable after that? The whole idea of this short is that you keep them alive so you can re-use them. People sell computers without harddrives because of the data on them. If you zero them out you can sell a working system and get a bit more money. ;-)

Haha it sure is a great decoy!

So zero, then random, then zero again. Quite the expert that can get your stuff back if you do so. ;)

Nah, modern harddrives are way too dense for that. Two or three passes mixed with random data will suffice.

That's a lot more work haha, I guess we all try to reinvent the wheel at some point. ;)

Hehe

That would be something to flood your disks with! 😄

@@ex-itguy That would be an interesting thing to put in /dev/cat

Stable Diffusion? :J

To be honest, I'm not sure that will work. Should maybe test it sometimes.

I'm probably wrong, but isn't not using quick format just zero filling?

@@Raptorox Exactly, it's wiping the drive instead of installing stuff that will overwrite with random data, you just need to uncheck one box, I think it's way easier

Auch. Maybe try to find the exact same type of drive on eBay?

@@ex-itguy been looking for 8 years now, still searching, I won't give up ever, I KNOW I have tons of lost media on this thing, I WILL restore it

If the contents are that important, maybe consider sending it to a data recovery service? They probably will have the board. I don't know how expensive it is, but they usually don't charge if they don't get the data back.

@@Carlos244 I contacted the local ones, they all told me they don't have that HDD nor the piece needed (the controller board), heck I even know what is wrong with the board, so I also Googled and asked for that tiny chip, still no luck since it's not a standard one but custom to Seagate HDDs

Same series, other size might work. I've done that at times when I was still working at a computer shop (two decades ago...)

Have you tried it? It really doesn't take that long. Besides, just start the action and go do something else?

Exactly 😄

If you're going to throw them away anyway, sure. This is mostly aimed at people who remove the harddrives from their computers before selling them. Just overwrite the data and sell them in working order... It takes a while but you don't have to sit and wait for it. ;)

Hey I'm not judging you for having fun 😆

Sure, soooo many other things you can do with it! I use a platter with bent edges to put under my motorcycle stand on soft surfaces. Works like a charm! Reusing the strong magnets inside is cool as well haha

@@ex-itguy now I kinda feel guilty. my comment was meant as a joke.

Don't worry about it, I thought it was kinda funny 😄

You're absolutely right on both points. :)

It's not that bad. Besides, you can walk away from it. ;)

@@ex-itguy A drive with several Terabyte takes days to weeks.

Never tried it on a disk that big but I think it took around 30 minutes per pass on a 12 year old 500GB disk...

Sure, but _this_ is available on any Linux, so you don't have to search and install it first. ;)

Seems like a plan!