128

How does SecureErase work? (lemmy.world)

submitted 1 month ago* (last edited 1 month ago) by [email protected] to c/[email protected]

37 comments fedilink hide all child comments

👽

you are viewing a single comment's thread
view the rest of the comments

[-] [email protected] 34 points 1 month ago

Your disk is like a file cabinet, there's also an index folder where for example it says that "your file.txt" is in cabinet C7. You go there and there's a sheet of paper written in pencil with the contents of your file. In this analogy here's how several solutions work:

Delete the file: throw away the index folder. Now if you need to write to disk you might think C7 is free and when you go there to write something else you find the old paper, which you erase and write on top. But if someone gets to your cabinet before that and they open C7 your file Will be there in its entirety, there just isn't an index telling you which cabinet to open.
Zero wipe: you go to C7, erase the file, and then throw away the index. Now if someone gets to your cabinet they might go to C7 but all they see is a white sheet of paper. However it's technically possible with a white sheet of paper to see what was written before, so this is considered better but not perfect.
Random wipe: same as before, except you erase and write random stuff on the sheet of paper. So it becomes a lot more difficult to recover what was there.
Multiple passes: Same as before, but you do this several times, so after dozens of random writes your original data should be completely impossible to recover.

[-] [email protected] 3 points 1 month ago* (last edited 1 month ago)

It's worth mentioning that the OS index is what gets deleted when a file is deleted, the SSD is untouched by this, but SecureErase is a special command sent to the SSD controller inside the unit that deletes its own index of what entries correspond to which 1s and 0s on which separate internal NAND flash chips (and dies, planes, blocks and pages) and in what order. This makes recovering data very very difficult even if the actual data is not overwritten in any way, because SSDs will often write in parallel for speed, which renders the oldest most bruteforcry digital forensic technique in the book on HDDs - simply transplanting the platters into a different drive, imaging them into hex and looking for file headers and subsequent zeroes (to identify empty space after a file) and reading in files as if they were written linearly to see what comes out.

That's as I understand it though.

this post was submitted on 29 May 2024

128 points (87.6% liked)

No Stupid Questions

34333 readers

1325 users here now

No such thing. Ask away!

!nostupidquestions is a community dedicated to being helpful and answering each others' questions on various topics.

The rules for posting and commenting, besides the rules defined here for lemmy.world, are as follows:

Rules (interactive)

Rule 1- All posts must be legitimate questions. All post titles must include a question.

All posts must be legitimate questions, and all post titles must include a question. Questions that are joke or trolling questions, memes, song lyrics as title, etc. are not allowed here. See Rule 6 for all exceptions.

Rule 2- Your question subject cannot be illegal or NSFW material.

Your question subject cannot be illegal or NSFW material. You will be warned first, banned second.

Rule 3- Do not seek mental, medical and professional help here.

Do not seek mental, medical and professional help here. Breaking this rule will not get you or your post removed, but it will put you at risk, and possibly in danger.

Rule 4- No self promotion or upvote-farming of any kind.

That's it.

Rule 5- No baiting or sealioning or promoting an agenda.

Questions which, instead of being of an innocuous nature, are specifically intended (based on reports and in the opinion of our crack moderation team) to bait users into ideological wars on charged political topics will be removed and the authors warned - or banned - depending on severity.

Rule 6- Regarding META posts and joke questions.

Provided it is about the community itself, you may post non-question posts using the [META] tag on your post title.

On fridays, you are allowed to post meme and troll questions, on the condition that it's in text format only, and conforms with our other rules. These posts MUST include the [NSQ Friday] tag in their title.

If you post a serious question on friday and are looking only for legitimate answers, then please include the [Serious] tag on your post. Irrelevant replies will then be removed by moderators.

Rule 7- You can't intentionally annoy, mock, or harass other members.

If you intentionally annoy, mock, harass, or discriminate against any individual member, you will be removed.

Likewise, if you are a member, sympathiser or a resemblant of a movement that is known to largely hate, mock, discriminate against, and/or want to take lives of a group of people, and you were provably vocal about your hate, then you will be banned on sight.

Rule 8- All comments should try to stay relevant to their parent content.

Rule 9- Reposts from other platforms are not allowed.

Let everyone have their own content.

Rule 10- Majority of bots aren't allowed to participate here.

Credits

Our breathtaking icon was bestowed upon us by @Cevilia!

The greatest banner of all time: by @TheOneWithTheHair!

founded 1 year ago

MODERATORS

[email protected]