shred
Can also be used from KDE Partition Manager.
Use LUKS encryption in the future.
this post was submitted on 20 Jan 2025
48 points (96.2% liked)
Linux
52855 readers
203 users here now
From Wikipedia, the free encyclopedia
Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).
Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.
Rules
- Posts must be relevant to operating systems running the Linux kernel. GNU/Linux or otherwise.
- No misinformation
- No NSFW content
- No hate speech, bigotry, etc
Related Communities
Community icon by Alpár-Etele Méder, licensed under CC BY 3.0
founded 5 years ago
MODERATORS
I assume in this context the benefit using LUKS is that even if someone does recover data from the drive, they'd just get encrypted data which is unreadable? If so, I hadn't considered that before!
shred or alternatively you can zero out all the bytes in a drive with dd if=/dev/zero of=/dev/<DRIVE>
sudo dd if=/dev/urandom of=/dev/[sdx] bs=4096K status=progress
Or for multiple passes:
sudo shred -fzv /dev/[sdx]
Change [sdx] to the drive you want to wipe, make sure you double check it's the right one.
Assuming the drive writes normally a simple command like
dd if=/dev/random of=/dev/sdX
Where sdX is the location of the drive should do the trick. Depending on drive time this may take a bit.
Yeah my first thought was just keep running dd commands, and sooner or later you'll have the hdd wiped.
Instructions unclear, accidentally deleted 200 EB of irrecoverable NASA data.
Just keep in mind that you can't wipe the bad sectors that have been remapped. That's unlikely to be an issue for a personal drive, but something to consider if it held particularly sensitive information.
Sectors are what, 4kb? The odds of something sensitive being in those each of those 4kb is low (but never zero).
If the drive implements the ATA secure erase command properly, it should also clear all the remapped sectors too. But I don't know if I trust them to implement it properly. Maybe try it and inspect the disk with a hex editor.
dd if=/dev/zero of=/dev/sdX bs=1M
This command is much faster. Instead of random bits, it just marks everything zero (dude). Is good enough.
Always use /dev/urandom for this purposes. /dev/random will be locked if it doesn't have enough entropy. It is good for getting some random kilobytes for cryptography but not 2 TB of random data for disk wipe.
Thanks for the heads up!
Since dipshits are down voting me for being right, I'll just leave this here
Thank you thats useful to know!
I like badblocks in destructive mode. It can also do multiple rounds of overwriting. It is also a good tool to burn in a new hdd or test a used one. just check smartctl bad sector count, run it, check again if it increased.
If the drive has bad sectors that it can't read right now, it likely had other sectors that were marginal and got copied (remapped) to new spare sectors before they became unreadable. So there is still potentially recoverable data in the remapped sectors, and not much you can do about it.
Basically, writing zeros to the disk is about as good as you can hope for. If your data is s00per seekrit to the point where you can't stand the possibility of any bits at all being recovered, you basically have to melt the drive. Otherwise, zero it and send it in.
Next time, set up encryption ahead of time, so your new drives never see plaintext. Some drives have a "secure erase" feature that is basically a crappy version of this built into the drive.
When I sold my drives, I used veracrypt with a 128 character password and PIM of 800+.
Isn't that the same thing as shredding?
No.
Can you elaborate?
Installing an operating system and enabling encryption won't overwrite the data on the entire disk. Instead, it will only overwrite on the specific sectors on which this operating system was installed.
Other "previous" data on the disk will remain intact and unaffected.
Unless the OS installer chooses to wipe the driver, which Debian's (non-calamares) installer does.
I understand what you mean. The way I did it was a full disk encryption as an "external drive" so the whole disk was encrypted
dd if=/dev/zero of=/dev/(your drive)
You can do status=progress if you want like someone else posted and if you pick a block size go with either the physical block size reported by the disk in smartcontrol or some multiple of it that coincides with a big even division of your controllers memory. The drives physical block size will be “easy” for the drive, bigger blocks are faster.
People saying physical destruction are operating in a different world than you and people saying urandom or shred are operating off old (>30 years) information. The same technology that makes ssds unrecoverable black boxes was originally developed and deployed in spinning drives to eek out speed gains because the disk itself can be expected to know better than the operating system where to put shit and makes techniques (which were postulated but never actually implemented successfully in the wild) to recover overwritten data infeasible.
Alternately just reformat it and don’t worry. No one doing drive rmas cares about your data. They’re already on the razors edge with feedback and customer trust, you think they’re gonna burn their above board bread and butter to run a harvesting operation for a few bucks on the side? That’s usually the purview of your local pc repair shop…
The day job is Private Possum territory, so our agreement is
- we won't send in drives
- we will send proof of destruction
and I'm sure it costs more, but we don't have to worry about recovered user data.
Our stuff is also in those crazy-secure datacenters, too, so we don't need to mess with crypto-at-rest.
DNAM. Is or used to be on the UBCD.
For the future remember, encryption helps when the disk is no longer operational.