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MacBytes
Dec 8, 2003, 10:29 PM
Category: 3rd Party Software
Link: Permaburn- Securely delete files with this multi-pass removal utility (http://macupdate.com/info.php/id/13522)

Posted on MacBytes.com (http://www.macbytes.com)

Approved by Mudbug



Vector
Dec 9, 2003, 03:01 PM
this looks good, but if anyone is really paranoid and wants more secure erasure check out secret shredder. secret shredder can overwrite up to 25 times using the option of several patterns including DOD compliant ones.

smada
Dec 9, 2003, 06:48 PM
or you can just select "secure empty trash" from the finder menu in 10.3

Vector
Dec 9, 2003, 07:55 PM
you could, but i think it only does 3 passes which doesn't mean the file is completely gone. if you are going to bother to secure delete something, i assume it ust be important so why not use secure shredder and make sure its gone.

MrMacMan
Dec 9, 2003, 09:42 PM
The only way for a file to be completly gone is to fill the hard drive up with other data.

Also a good way to check for drive errors surprisingly...

Sure you can delete it and redelete it 20 times... but some little part could get away, doubtful, but that is the 'only way' to get 100% deleted.

Edot
Dec 10, 2003, 06:28 PM
Originally posted by MrMacman
The only way for a file to be completly gone is to fill the hard drive up with other data.

Also a good way to check for drive errors surprisingly...

Sure you can delete it and redelete it 20 times... but some little part could get away, doubtful, but that is the 'only way' to get 100% deleted.

That is what secure deleting is. It writes 0's over the data.

Vector
Dec 10, 2003, 07:04 PM
Normally secure deletion utilities overwrite the disk space using a pattern of 1's and 0's not just zero's. some utilities let you set different patterns (normally either 0101... or a random 'pattern' of binary). Some will also use algorithms to be more secure about it and overwrite the space many times.

overwriting a file a few times with a pattern does not necessarily mean that the file is completely gone. in some cases 'securely deleted' files can be partially recovered, which is why major corporations and the DOD use a special pattern (DOD 5520.22 M) with a high number of passes on highly sensitive material.

MrMacMan
Dec 11, 2003, 08:30 PM
Originally posted by Edot
That is what secure deleting is. It writes 0's over the data.

Not really... also depends on the App's Default overwrite...

Vector -- Yes, there are many algorithms out there... I still say for 100% deletion the only way is to fill your HD up.

rainman::|:|
Dec 12, 2003, 12:40 AM
drives can be scanned using precise tools to determine the contents of a disk one or more times overwritten... it leaves a magnetic signature. hence the need for multi-pass utilities.

well, "need" may be strong a word, few people are under such scrutiny that they would need this level of security...

paul

jethroted
Dec 12, 2003, 10:21 AM
You actually have to overwrite something at least 7 times before it is totally gone. Any fewer than that, and high end equipment can pick up traces of data that has been overwritten. Think of it in terms of a chalk board. If you have a totally clean chalk board, then write a zero down, wipe out the zero with your hand, then write a one down in the same spot, you should still be able to see traces of the zero behind the one. A HD is the same. Even if you zero the entire drive once, high end equipment will still be able to get that data. You should overwrite it 7 times at least. More times if you really want to make sure it's gone.