35 pass erase free disk space disk utility

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can the previous information EVER be recovered? Even with the highest technology ever invented?
 

chscag

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It wouldn't surprise me if it could by the NSA or the CIA. The safest way to destroy the data on a hard drive is to physically destroy the hard drive and then melt what's left over. :)

Besides, a 35 pass erase on a modern hard drive could take days to complete.

Regards.
 
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I recommend you swap or destroy the HD if you're that paranoid to be thinking on a 35 pass erase.

No offense, but as chscag said, deppending on the HD capacity it can go on for days until its done.
 
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actually guys its after a fresh re install. i am not bothered about time but just wondered if the info could ever be recovered with any technology. also what if the information that you want hidden was overwritten by the os. does this mean that it (or part of it) can be easily be obtained as its only been overwritten once by the os?
all answers are interesting as this subject is very interesting :)
 
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After about 7 passes the chances of it being recovered are rapidly diminished. At 35 it's going to be very difficult and someone would have to have very high end equipment and be determined to do so. That being said, DOD standard is to do the multi-pass erase then physically destroy the disk. There are shredders made specifically for the task ;)


BTW the multiple passes overwrite in 0 and 1 patterns, multiple different patterns each time.
 
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doug
 

pigoo3

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can the previous information EVER be recovered? Even with the highest technology ever invented?

According to this Apple document:

About Disk Utility's secure erase options

The DoD (Department of Defense)...actually only requires a 3-pass erase:

"The 7-Pass Erase option conforms to the DoD 5220.22-M specification. This specification calls for three passes, but Disk Utility performs seven."

So a 35 pass erase (in addition to taking an ungodly amount of time to perform)...would way way exceed what the DoD requires!

- Nick
 
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National Industrial Security Program - Wikipedia, the free encyclopedia
As of the June 2007 edition of the DSS C&SM, overwriting is no longer acceptable for sanitization of magnetic media; only degaussing or physical destruction is acceptable.
So it means the standard now is trash the drive and melt the remains into a sticky blob. Or alternatively you sit it on a desk and place a heap of Neodymium magnets above it. And screw the data on the drive that way.
 

pigoo3

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National Industrial Security Program - Wikipedia, the free encyclopedia

So it means the standard now is trash the drive and melt the remains into a sticky blob. Or alternatively you sit it on a desk and place a heap of Neodymium magnets above it. And screw the data on the drive that way.

Thanks for the updated security procedure. I think that the Apple document I linked was of OS 10.4 "vintage"...so looks like things have changed.

It's certainly much more fun to come up with "physical" ways to make a hard drive unreadable...than simply running "Disk Utilities" over-write procedure 7 or 35 times!;)

- Nick
 
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If you really, really don't want someone to find your old porn and 2008 tax return, take that disk and chop it in half with an axe.
 
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If your axe swing misses the round data holding circle disk part of the hard disk then they might be able to take the data holding circle disk part, hook it up to another working drive and extract the data that way.

But if you get axe happy and chop it into a million parts or use the magnets :).

But I like your way of thinking JJ. Woot! Let all your frustrations out with an axe.
 
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Yes! A big magnet will work. If the rust particles on the platters are fully randomized, then I think recovery becomes impossible. But just to be safe, chop it up anyway.

Then burn it.
 

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Wonder if this thread is sufficient enough to convince my wife that I need a blowtorch. axes are definitely out of the question since we have already had one unfortunate incident involving myself, a large kitchen knife, and a knife sharpener.
 
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To be doubly doubly sure toss the drive into a furnace. If it has sensitive information, cheaper to just replace.
 
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Make it an atomic furnace just to be absolutely sure. That's also the green choice, since your hard disk becomes renewable energy! :D
 
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Atomic furnaces have one glitch. Where to dump the nuclear waste they accumulate? But otherwise a great idea.
 

chscag

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Wonder if this thread is sufficient enough to convince my wife that I need a blowtorch. axes are definitely out of the question since we have already had one unfortunate incident involving myself, a large kitchen knife, and a knife sharpener.

I thought Louisiana was a community property state? ;D Or is that "Divorce Cajun style"? :D

(couldn't resist)

Regards.
 

Slydude

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I thought Louisiana was a community property state? ;D Or is that "Divorce Cajun style"? :D

(couldn't resist)

Regards.

The drives up for a torching will be torched by mutual consent. The trip to the ER for stitches was my own fault. No plans to test the community property laws. I do wonder how many times hard drives and the like have been the topic of "custody" battles though.:)
 

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