Gentoo Forums
Gentoo Forums
Gentoo Forums
Quick Search: in
Good software to delete my personal files
View unanswered posts
View posts from last 24 hours

Goto page 1, 2  Next  
Reply to topic    Gentoo Forums Forum Index Off the Wall
View previous topic :: View next topic  
Author Message
DannySmit
n00b
n00b


Joined: 12 Nov 2012
Posts: 1

PostPosted: Tue Nov 13, 2012 1:56 pm    Post subject: Good software to delete my personal files Reply with quote

Hey all, I was wondering whether anyone could advice some good free sotware which I could download - I need to clean uo my work laptop from my personal files. Thanx!
Back to top
View user's profile Send private message
John R. Graham
Administrator
Administrator


Joined: 08 Mar 2005
Posts: 7939
Location: Somewhere over Atlanta, Georgia

PostPosted: Tue Nov 13, 2012 1:58 pm    Post subject: Reply with quote

Moved from Other Things Gentoo to Off the Wall. Not about Gentoo so it fits better here.

- John
_________________
I can confirm that I have received between 0 and 999 National Security Letters.
Back to top
View user's profile Send private message
MustrumR
n00b
n00b


Joined: 15 Nov 2011
Posts: 57
Location: Right here

PostPosted: Tue Nov 13, 2012 2:36 pm    Post subject: Reply with quote

Code:
dd if=/dev/urandom of=/dev/sda bs=4K
4 or 5 times?
Back to top
View user's profile Send private message
Prenj
n00b
n00b


Joined: 20 Nov 2011
Posts: 13

PostPosted: Tue Nov 13, 2012 3:05 pm    Post subject: Reply with quote

http://blog.kadiraltan.com/disk-wiping-dd-and-devrandom/
Back to top
View user's profile Send private message
aidanjt
Veteran
Veteran


Joined: 20 Feb 2005
Posts: 1102
Location: Rep. of Ireland

PostPosted: Tue Nov 13, 2012 4:37 pm    Post subject: Reply with quote

man shred(1), is part of coreutils on Linux. If you don't want to be left at the mercy of the filesystem, then you're going to have to go though a bit more effort to calculate the sector range(s) of the file and zero with dd and seek with the raw disk and count to stop at the end of file, although that's very very risky if you don't know what you're doing, so just stick with shred.
_________________
juniper wrote:
you experience political reality dilation when travelling at american political speeds. it's in einstein's formulas. it's not their fault.
Back to top
View user's profile Send private message
energyman76b
Advocate
Advocate


Joined: 26 Mar 2003
Posts: 2031
Location: Germany

PostPosted: Tue Nov 13, 2012 5:58 pm    Post subject: Reply with quote

MustrumR wrote:
Code:
dd if=/dev/urandom of=/dev/sda bs=4K
4 or 5 times?


even once is overkill.

FACT: overwriting a disk with ZEROs ONCE is enough.
_________________
AidanJT wrote:

Libertardian denial of reality is wholly unimpressive and unconvincing, and simply serves to demonstrate what a bunch of delusional fools they all are.

Satan's got perfectly toned abs and rocks a c-cup.
Back to top
View user's profile Send private message
NotQuiteSane
Guru
Guru


Joined: 30 Jan 2005
Posts: 471
Location: Klamath Falls, Jefferson, USA, North America, Midgarth

PostPosted: Tue Nov 13, 2012 7:00 pm    Post subject: Reply with quote

Nuke it from orbit.

NQS
_________________
These opinions are mine, mine I say! Piss off and get your own.

As I see it -- An irregular blog, Improved with new location

To delete French language packs from system use 'sudo rm -fr /'
Back to top
View user's profile Send private message
djdunn
l33t
l33t


Joined: 26 Dec 2004
Posts: 710
Location: Arrakis

PostPosted: Tue Nov 13, 2012 7:17 pm    Post subject: Reply with quote

professional data recovery people hear dd and give up before they start
_________________
A process cannot be understood by stopping it. Understanding must move with the flow of the process, must join it and flow with it.

-The First Law of Mentat
Back to top
View user's profile Send private message
Mardok45
n00b
n00b


Joined: 21 Jun 2008
Posts: 64
Location: Right behind you

PostPosted: Tue Nov 13, 2012 8:40 pm    Post subject: Reply with quote

energyman76b wrote:
MustrumR wrote:
Code:
dd if=/dev/urandom of=/dev/sda bs=4K
4 or 5 times?


even once is overkill.

FACT: overwriting a disk with ZEROs ONCE is enough.


If someone has the equipment, they can determine what a certain bit was at some point in time, recovering your data. But if they can afford that kind of equipment, they're probably seeking bigger targets than your porn history.
Back to top
View user's profile Send private message
energyman76b
Advocate
Advocate


Joined: 26 Mar 2003
Posts: 2031
Location: Germany

PostPosted: Tue Nov 13, 2012 9:10 pm    Post subject: Reply with quote

Mardok45 wrote:
energyman76b wrote:
MustrumR wrote:
Code:
dd if=/dev/urandom of=/dev/sda bs=4K
4 or 5 times?


even once is overkill.

FACT: overwriting a disk with ZEROs ONCE is enough.


If someone has the equipment, they can determine what a certain bit was at some point in time, recovering your data. But if they can afford that kind of equipment, they're probably seeking bigger targets than your porn history.


no, they can't. Even if they know the state of the bit beforehand they only have a 50% to recover it. Almost everything the pros do is to ignore filesystem errors and scan for data that looks like files. Just like testdisk - just with better equipment.

See also:
http://grot.com/wordpress/?p=154
https://www.anti-forensics.com/disk-wiping-one-pass-is-enough/
http://link.springer.com/chapter/10.1007/978-3-540-89862-7_21
_________________
AidanJT wrote:

Libertardian denial of reality is wholly unimpressive and unconvincing, and simply serves to demonstrate what a bunch of delusional fools they all are.

Satan's got perfectly toned abs and rocks a c-cup.
Back to top
View user's profile Send private message
Mardok45
n00b
n00b


Joined: 21 Jun 2008
Posts: 64
Location: Right behind you

PostPosted: Tue Nov 13, 2012 9:31 pm    Post subject: Reply with quote

energyman76b wrote:
Mardok45 wrote:
energyman76b wrote:
MustrumR wrote:
Code:
dd if=/dev/urandom of=/dev/sda bs=4K
4 or 5 times?


even once is overkill.

FACT: overwriting a disk with ZEROs ONCE is enough.


If someone has the equipment, they can determine what a certain bit was at some point in time, recovering your data. But if they can afford that kind of equipment, they're probably seeking bigger targets than your porn history.


no, they can't. Even if they know the state of the bit beforehand they only have a 50% to recover it. Almost everything the pros do is to ignore filesystem errors and scan for data that looks like files. Just like testdisk - just with better equipment.

See also:
http://grot.com/wordpress/?p=154
https://www.anti-forensics.com/disk-wiping-one-pass-is-enough/
http://link.springer.com/chapter/10.1007/978-3-540-89862-7_21

That's cool.

If the probability of recovering a bit is 50%, what's the maximum amount of data you can run a MFM scan with a probability of fully recovering the data at, say, 1%?
Back to top
View user's profile Send private message
wildhorse
Tux's lil' helper
Tux's lil' helper


Joined: 16 Mar 2006
Posts: 148
Location: Estados Unidos De América

PostPosted: Tue Nov 13, 2012 9:46 pm    Post subject: Reply with quote

The best way to wipe your personal files is: store them with Microsoft Windows and Microsoft Office. :P
Back to top
View user's profile Send private message
energyman76b
Advocate
Advocate


Joined: 26 Mar 2003
Posts: 2031
Location: Germany

PostPosted: Tue Nov 13, 2012 10:07 pm    Post subject: Reply with quote

Mardok45 wrote:
energyman76b wrote:
Mardok45 wrote:
energyman76b wrote:
MustrumR wrote:
Code:
dd if=/dev/urandom of=/dev/sda bs=4K
4 or 5 times?


even once is overkill.

FACT: overwriting a disk with ZEROs ONCE is enough.


If someone has the equipment, they can determine what a certain bit was at some point in time, recovering your data. But if they can afford that kind of equipment, they're probably seeking bigger targets than your porn history.


no, they can't. Even if they know the state of the bit beforehand they only have a 50% to recover it. Almost everything the pros do is to ignore filesystem errors and scan for data that looks like files. Just like testdisk - just with better equipment.

See also:
http://grot.com/wordpress/?p=154
https://www.anti-forensics.com/disk-wiping-one-pass-is-enough/
http://link.springer.com/chapter/10.1007/978-3-540-89862-7_21

That's cool.

If the probability of recovering a bit is 50%, what's the maximum amount of data you can run a MFM scan with a probability of fully recovering the data at, say, 1%?


3bit?
_________________
AidanJT wrote:

Libertardian denial of reality is wholly unimpressive and unconvincing, and simply serves to demonstrate what a bunch of delusional fools they all are.

Satan's got perfectly toned abs and rocks a c-cup.
Back to top
View user's profile Send private message
Bones McCracker
Veteran
Veteran


Joined: 14 Mar 2006
Posts: 1569
Location: U.S.A.

PostPosted: Tue Nov 13, 2012 10:41 pm    Post subject: Reply with quote

energyman76b wrote:
MustrumR wrote:
Code:
dd if=/dev/urandom of=/dev/sda bs=4K
4 or 5 times?


even once is overkill.

FACT: overwriting a disk with ZEROs ONCE is enough.

No, it's not. Overwriting it once will protect you from the average data recovery tools, but it won't protect you from forensic-quality analysis.

PFC Manning's personal laptop is a recent case in point. He deleted all his files, reinstalled the OS, reformatted his drive, and then, at somebody's advice, nuked the disk, overwriting it with zero data once (a single-pass wipe). The Army was nevertheless able to recover lots and lots of information from it, including his encryption password, chat logs between Manning and other involved persons, emails he had sent to wikileaks, etc.
_________________
"The accumulation of all power, legislative, executive, and judiciary in the same hands...may justly be pronounced the very definition of tyranny."
--James Madison, Federalist 46
Back to top
View user's profile Send private message
energyman76b
Advocate
Advocate


Joined: 26 Mar 2003
Posts: 2031
Location: Germany

PostPosted: Tue Nov 13, 2012 10:44 pm    Post subject: Reply with quote

you might read some of the links I posted. Or google yourself.

Overwritting once defeats even professional tools.
_________________
AidanJT wrote:

Libertardian denial of reality is wholly unimpressive and unconvincing, and simply serves to demonstrate what a bunch of delusional fools they all are.

Satan's got perfectly toned abs and rocks a c-cup.
Back to top
View user's profile Send private message
Bones McCracker
Veteran
Veteran


Joined: 14 Mar 2006
Posts: 1569
Location: U.S.A.

PostPosted: Tue Nov 13, 2012 10:46 pm    Post subject: Reply with quote

wildhorse wrote:
The best way to wipe your personal files is: store them with Microsoft Windows and Microsoft Office. :P

:lol:
You can find out all kinds of interesting stuff by opening Word files in a text editor.
_________________
"The accumulation of all power, legislative, executive, and judiciary in the same hands...may justly be pronounced the very definition of tyranny."
--James Madison, Federalist 46
Back to top
View user's profile Send private message
Bones McCracker
Veteran
Veteran


Joined: 14 Mar 2006
Posts: 1569
Location: U.S.A.

PostPosted: Tue Nov 13, 2012 10:46 pm    Post subject: Reply with quote

energyman76b wrote:
you might read some of the links I posted. Or google yourself.

Overwritting once defeats even professional tools.

Sorry, but you're wrong. A single-pass zero-wipe is inadequate protection from the most capable forensic techniques now available. Continue to believe what you want to believe, though.
_________________
"The accumulation of all power, legislative, executive, and judiciary in the same hands...may justly be pronounced the very definition of tyranny."
--James Madison, Federalist 46
Back to top
View user's profile Send private message
energyman76b
Advocate
Advocate


Joined: 26 Mar 2003
Posts: 2031
Location: Germany

PostPosted: Tue Nov 13, 2012 10:54 pm    Post subject: Reply with quote

BoneKracker wrote:
energyman76b wrote:
you might read some of the links I posted. Or google yourself.

Overwritting once defeats even professional tools.

Sorry, but you're wrong. A single-pass zero-wipe is inadequate protection from the most capable forensic techniques now available. Continue to believe what you want to believe, though.


funny that studies and professionals say otherwise....

Ald harddisks from the 80 or early nineties might need more than one pass. Everything else? Nope.

Craig Wright for example is an expert read this please and learn:
http://www.h-online.com/security/news/item/Secure-deletion-a-single-overwrite-will-do-it-739699.html

Quote:

a single bit whose precise location is known can in fact be correctly reconstructed with 56 per cent probability (in one of the quoted examples). To recover a byte, however, correct head positioning would have to be precisely repeated eight times, and the probability of that is only 0.97 per cent. Recovering anything beyond a single byte is even less likely.

_________________
AidanJT wrote:

Libertardian denial of reality is wholly unimpressive and unconvincing, and simply serves to demonstrate what a bunch of delusional fools they all are.

Satan's got perfectly toned abs and rocks a c-cup.
Back to top
View user's profile Send private message
Bones McCracker
Veteran
Veteran


Joined: 14 Mar 2006
Posts: 1569
Location: U.S.A.

PostPosted: Tue Nov 13, 2012 11:44 pm    Post subject: Reply with quote

That's nice. He may be an "expert", but the Manning case this year reveals that the U.S. Army can recover data from single-pass zero-wiped disk.

But unless you're likely to have the determined efforts of a such an organization applied against you, I'd agree that anything more than a single-pass random-data write is overkill.

More often, what screws people is that they've shredded a file, but don't realize that copies of it existed in various other locations, such as tmp files, mail spools, swap space, etc.

As I've said many times before, the only way to really be safe is to use Tin Hat Linux (based on Gentoo Hardened and running entirely in RAM), wait five minutes after shutting down the computer before releasing physical control of it (or yank the RAM), and store any persistent data on a heavily-encrypted USB flash stick which you keep deep in your ass (deeper than the length of a grown man's fingers).
_________________
"The accumulation of all power, legislative, executive, and judiciary in the same hands...may justly be pronounced the very definition of tyranny."
--James Madison, Federalist 46
Back to top
View user's profile Send private message
pjp
Administrator
Administrator


Joined: 16 Apr 2002
Posts: 16117
Location: Colorado

PostPosted: Wed Nov 14, 2012 1:32 am    Post subject: Reply with quote

BoneKracker wrote:
store any persistent data on a heavily-encrypted USB flash stick which you keep deep in your ass (deeper than the length of a grown man's fingers).
They only have to wait.
_________________
lolgov. 'cause where we're going, you don't have civil liberties.

In Loving Memory
1787 - 2008
Back to top
View user's profile Send private message
Bones McCracker
Veteran
Veteran


Joined: 14 Mar 2006
Posts: 1569
Location: U.S.A.

PostPosted: Wed Nov 14, 2012 1:46 am    Post subject: Reply with quote

If you're going to keep it in there a long time, you swallow it instead, with a 30-foot-long string, tied to one of your rear molars. Then, when you shit it out, you untie the string from your mouth and pull on it, pulling the flash drive back up into your ass the appropriate distance, tie the string off to your rear molar again, and trim off the excess string in your mouth. When you need it, you just untie the string and wait a few hours.

It's the only way to be sure. If you're really worried enough to be concerned whether you need to overwrite data one vs many times, then you must also be worried enough to this this.
_________________
"The accumulation of all power, legislative, executive, and judiciary in the same hands...may justly be pronounced the very definition of tyranny."
--James Madison, Federalist 46
Back to top
View user's profile Send private message
sikpuppy
n00b
n00b


Joined: 12 Jun 2012
Posts: 34
Location: Central Coast, NSW

PostPosted: Wed Nov 14, 2012 6:16 am    Post subject: Reply with quote

Does the US military still shoot wiped hard drives? That would make it fairly unlikely that the data would ever be recovered, I would imagine. A bolt gun would do the trick as well one would think.

As for recovery after a single pass, that would depend on how sensitive you could make the read of the data. There may still be a magnetic image of the previous data faintly on the platters, but the heads would have to be calibrated differently (in a fashion analogous to the refocussing of the laser on a dual layered DVD).

So, if you are a criminal and you don't want the Man to get you, shoot the crap out of old data and just install a new hard drive.
Back to top
View user's profile Send private message
Bones McCracker
Veteran
Veteran


Joined: 14 Mar 2006
Posts: 1569
Location: U.S.A.

PostPosted: Wed Nov 14, 2012 6:54 am    Post subject: Reply with quote

I've never heard of anybody shooting disks, except for the fun of it, to see what happens. If I really, really wanted to be ultra-ridiculously safe (like if a disk had the means to wipe out the human race on it), I'd take an arc-welder to the platters.

When I get rid of an old computer, I just use DBAN on the drives, which happens to be on my bootable SystemRescueCD USB flash drive (which is Gentoo-based but not up my ass). It also has some nice tools for low-level disk repair, along with a butt-load (no pun intended) of other utilities.
_________________
"The accumulation of all power, legislative, executive, and judiciary in the same hands...may justly be pronounced the very definition of tyranny."
--James Madison, Federalist 46
Back to top
View user's profile Send private message
energyman76b
Advocate
Advocate


Joined: 26 Mar 2003
Posts: 2031
Location: Germany

PostPosted: Wed Nov 14, 2012 6:34 pm    Post subject: Reply with quote

BoneKracker wrote:
That's nice. He may be an "expert", but the Manning case this year reveals that the U.S. Army can recover data from single-pass zero-wiped disk.


hm, lets see - from what I gather using google, Manning didn't even really wipe the disk ONCE. He deleted and reinstalled. Oopps. Of course, all the old data structures were there.

Memory cards are a different beast, but this is about hard disks.
_________________
AidanJT wrote:

Libertardian denial of reality is wholly unimpressive and unconvincing, and simply serves to demonstrate what a bunch of delusional fools they all are.

Satan's got perfectly toned abs and rocks a c-cup.
Back to top
View user's profile Send private message
John R. Graham
Administrator
Administrator


Joined: 08 Mar 2005
Posts: 7939
Location: Somewhere over Atlanta, Georgia

PostPosted: Wed Nov 14, 2012 6:41 pm    Post subject: Reply with quote

This is the longest time I've seen a probable proto-spammer played with without gladiators or Turkish prisons being mentioned. :wink:

- John
_________________
I can confirm that I have received between 0 and 999 National Security Letters.
Back to top
View user's profile Send private message
Display posts from previous:   
Reply to topic    Gentoo Forums Forum Index Off the Wall All times are GMT
Goto page 1, 2  Next
Page 1 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum