Deleted files

All Gurus once were Newbies
Forum rules
There are no such things as "stupid" questions. However if you think your question is a bit stupid, then this is the right place for you to post it. Please stick to easy to-the-point questions that you feel people can answer fast. For long and complicated questions prefer the other forums within the support section.
Before you post please read how to get help
Post Reply
bally1001
Level 1
Level 1
Posts: 48
Joined: Sun Aug 20, 2017 8:54 am

Deleted files

Post by bally1001 »

Now I am now using my Linux laptop more and more in place of my Windows laptop, whereas I know that Windows will not destroy confidential documents or indeed any other file, only delete the file from normal access until it is overwritten....Therefore other software (Privazer) has to be used to change all the binary values to zero, or other more complex random changes..........Therefore, my question is, in Linux (Mint), when the deletion dialogue box says "Deletion will remove the file permanently from your computer", what exactly does this mean?.....A replica of the Windows process, or something rather more secure.?
minitux
Level 5
Level 5
Posts: 854
Joined: Tue Sep 12, 2017 10:05 am

Re: Deleted files

Post by minitux »

that you can not restore them because they do not go to the trash
User avatar
Faust
Level 5
Level 5
Posts: 500
Joined: Thu Jul 14, 2016 3:40 am

Re: Deleted files

Post by Faust »

bally1001 wrote: "Deletion will remove the file permanently from your computer", what exactly does this mean?.....A replica of the Windows process, or something rather more secure.?
A very good question , and I have had the same doubts myself .

I thought I had found a good fix by zipping the file with a password ( eg. a random clatter of keys ) and then deleting it .
But it doesn't work , because the zip file does not over-write the original plain-text file , so that is still " floating around " somewhere ,
and you end up with a recursive problem .

I have tried some other options from command line , such as shred , wipe , secure-delete and sfill
This article might be helpful -
https://www.tecmint.com/permanently-and ... ies-linux/

The real test would be to create some text files , try the various secure delete options and then make a serious effort to recover the data .
The proof of the pudding so to speak .

It's been on my " to do " list for a long while , but there are only so many hours ...etc . :)
" And so it goes " - Kurt Vonnegut
The modern reality and the satirical parody are rapidly converging .
Aleron Ives
Level 3
Level 3
Posts: 127
Joined: Sun Sep 17, 2017 2:20 am
Location: California

Re: Deleted files

Post by Aleron Ives »

The delete option is just warning you that it bypasses the trash can, so you can't simply "undelete" a file that you removed this way. I don't think it has anything to do with "securely" deleting a file, i.e. overwriting its contents with garbage.
User avatar
kukamuumuka
Level 16
Level 16
Posts: 6697
Joined: Tue Sep 03, 2013 4:51 am
Location: Finland
Contact:

Re: Deleted files

Post by kukamuumuka »

You probably can restore your files using R-Linux.
viewtopic.php?t=223299#p1175940
Mute Ant
Level 14
Level 14
Posts: 5130
Joined: Tue Sep 03, 2013 7:45 pm
Location: Norfolk UK

Re: Deleted files

Post by Mute Ant »

Ext4 'deletion' will unlink the file name from the data, just like NTFS or FAT. The name and the data are still on the drive until something else writes over them.

The OS and the file system have no control over what happens inside a drive. It might be making many copies and serving the most accessible, RAID style, or updating the old version by making a modified copy, COW style. This is especially true of silicon stores. They do wear-levelling in 4MiB chunks that guarantees old data is preserved when new data is written. The whole King James Bible text will fit in one thumbdrive erase block. Edit it a couple of times and now there's three versions on the drive, somewhere.

If you have data that should not be openly available, keep it on an encrypted drive reserved for that purpose.

1] If you have data that absolutely must be wiped, you must physically destroy the drive. Something disposable, like a 16GB thumbdrive, does the job.
2] If [1] is too expensive, second-best is to activate the Secure Erase function of the drive. That takes hours to complete.
3] If the drive lacks a Secure Erase function, a 3-pass shred on the whole drive will wipe nearly everything.
While you're waiting, read the free novel we sent you. It's a Spanish story about a guy named "manual".
User avatar
Faust
Level 5
Level 5
Posts: 500
Joined: Thu Jul 14, 2016 3:40 am

Re: Deleted files

Post by Faust »

administrollaattori wrote:You probably can restore your files using R-Linux.
viewtopic.php?t=223299#p1175940
@administrollaattori
Nice one Centurion !
That's just what I need to get started with my project ( see my earlier post ^^ )
But now I have one less excuse for not getting on with it !
Mute Ant wrote: If you have data that absolutely must be wiped, you must physically destroy the drive.
@Mute Ant
Check out the equipment and services that these guys provide .....
http://www.datastroyer.com
These are people who clearly take physical destruction very seriously indeed :)

It makes me chuckle ..... but I'm not sure why .
Last edited by Faust on Tue Nov 14, 2017 12:12 pm, edited 2 times in total.
" And so it goes " - Kurt Vonnegut
The modern reality and the satirical parody are rapidly converging .
bally1001
Level 1
Level 1
Posts: 48
Joined: Sun Aug 20, 2017 8:54 am

Re: Deleted files

Post by bally1001 »

Thanks for your comments......It seems I need to continue with my (Windows) custom of saving all my personal files to pendrives and then, on the equipment used to create the file, 'erase the content' and then 'save' the empty file before deleting it......That does raise another question though:-

I don't use Microsoft Office products, but Libre office instead.......I know that MS archives all work done with it's office products, whether the file is saved or not (ostensibly to help improve the product!)....Does Libre software, Linux version, do the same?
Mute Ant
Level 14
Level 14
Posts: 5130
Joined: Tue Sep 03, 2013 7:45 pm
Location: Norfolk UK

Re: Deleted files

Post by Mute Ant »

"...continue with my (Windows) custom..." If you like, but it doesn't stop someone looking at the old copies elsewhere on the drive...
### Search drive sda for the text "credit card"
sudo grep -i -a "credit card" /dev/sda | tr -dc "[:alnum:] \n"
While you're waiting, read the free novel we sent you. It's a Spanish story about a guy named "manual".
User avatar
kukamuumuka
Level 16
Level 16
Posts: 6697
Joined: Tue Sep 03, 2013 4:51 am
Location: Finland
Contact:

Re: Deleted files

Post by kukamuumuka »

bally1001 wrote:Thanks for your comments......It seems I need to continue with my (Windows) custom of saving all my personal files to pendrives and then, on the equipment used to create the file, 'erase the content' and then 'save' the empty file before deleting it......That does raise another question though:-
Windows is insecure option, because it makes all kind of temp-files, which are easy to find. Linuxes clear out /tmp in every boot. :wink:
bally1001
Level 1
Level 1
Posts: 48
Joined: Sun Aug 20, 2017 8:54 am

Re: Deleted files

Post by bally1001 »

Thanks for your replies,

Not wishing to appear negative, I think for my confidential documents I will stick with using Windows, because, knowing how MS stores all kinds of info, after saving such documents onto a secure pen-drive, to clean the laptop drive I have the software that will, by using multiple file wipes, eliminate all the diverse traces totally (Privazer, Ccleaner and JAM software) even tackling the more complicated wear levelling characteristics of SSDs......With Linux, I cannot identify any software that will do such a thorough job....Even after installing Bitbleach, it isn't clear precisely what it cleans, it certainly doesn't offer (as far as I can see) any wiping option for free space.
User avatar
kukamuumuka
Level 16
Level 16
Posts: 6697
Joined: Tue Sep 03, 2013 4:51 am
Location: Finland
Contact:

Re: Deleted files

Post by kukamuumuka »

bally1001 wrote:Even after installing Bitbleach, it isn't clear precisely what it cleans, it certainly doesn't offer (as far as I can see) any wiping option for free space.
BleachBit overwrites the files if you want.
Image

Image
bally1001
Level 1
Level 1
Posts: 48
Joined: Sun Aug 20, 2017 8:54 am

Re: Deleted files

Post by bally1001 »

Hi,
Perhaps it's a question of semantics....When the dialogue box says "hides" rather than "overwrites" deleted files it suggests they still exist but remain hidden.....Well we all know that a "hidden" file is not really overwritten but accessible with the right software. Maybe I'm just being picky.
Screenshot from 2017-11-16 10-18-07-b.jpg
Post Reply

Return to “Newbie Questions”