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11

The only way to completely protect data is to destroy all copies of it beyond possibility of recovery. So yes...shred your disks. And if you've memorized any of the data, shred your brain too. http://xkcd.com/538/


7

The deleted files still lurking in the filsystem (that Eraser would delete) will be encrypted as well, as the whole filesystem is encrypted. So it ends up with how secure one thinks it is to encrypt the disk with TrueCrypt. One can only find the deleted files if one can get access to the crypted filesystem (with password or cracking it).


6

It depends. Using TrueCrypt definitely gives you better security. That's because if someone's looking for your deleted files then s/he have to get your TrueCrypt credentials. Then s/he can decrypt your file system and maybe can get back your deleted data. Getting your password or the encryption key is not as hard as it seems to be. (Well, if the attacker ...


4

I've wrote a quick approach utilizing the Random Data File Creator. Mike noted that RDFC doesn't correctly fill the file with random data. I've emailed the author and reported this issue. For the time being, I've implemented a replacement. This Windows command line script will do what you want: @ECHO OFF SETLOCAL IF "%1"=="" GOTO missingParam GOTO ...


3

Shred should be slower than a write of the the same size, because of your -z. From the manual: z, --zero add a final overwrite with zeros to hide shredding If you're not trying to hide the fact that it's shredded, and just want to actually shred it, leave off the -z. Obviously it's probably pointless to use shred if you're using ReiserFS, XFS, Ext3, ...


2

I will give you the answer from a security professional's perspective. Hard disk encryption is indeed a good feature and it can keep all but the most savvy users out of your data, however something to note here is that is indeed possible to get in. One method which has been making some news lately is to cryogenically cool the memory module so that it can ...


2

Questions like this have popped up before. The short answer is if the data is viewable, then it can be copied. Even if there was a program that encrypted the video so that it could not be copied directly as a file, the end user can always use video capture software to capture the video.


2

For entire disks, there's the shred command, which by default only overwrites three times but with the -n <number> option can do as many passes as desired. It doesn't work so well on individual files in journaled filesystems, though. With the -z option, shred will do an extra pass with 0s afterward, so the shredding isn't immediately obvious.


2

If you want to, you can quit after for example one iteration. That is not secure (as in it's impossible to restore anything), but normal tools available for everyone can't recover files then. See for example this page for some more information. You can pause it at least with sending command SIGSTOP, assuming you know the process id (PID): kill -SIGSTOP PID ...


2

SysInternals SDelete works on files as well as free space. It's a simple command line app, but it works as well as anything else for secure deletion of files. Also, see the previous question about secure deletion here. Also, about drive-level secure delete. Just saw this item. Apparently, when an SSD is involved, existing data destruction techniques might ...


2

Well, just in case someone beats the password out of you... Or places small spy camera above your keyboard... Maybe it is reasonable. It all depends on levels of data sensitivity and paranoia, I think.


1

Update - 2011/06/06 Not sure if this was available at the time I asked the question, but recent visits to SourceForge have enlightened me to the availability of MD5 & SHA1 verification hashes on the SourceForge site. Here's the link: http://sourceforge.net/projects/dban/files/dban/dban-2.2.6/ On the same horizontal line of "dban-2.2.6_i586.iso", just ...


1

You're going to have to wipe the entire free space if you really want to make sure it's gone. Generally, using /dev/random (and variations) is not as secure as a full fledged wipe, because /dev/random may or may not use the disk contents to add entropy, and only does one pass, without security in its design.


1

Have a look at this question regarding secure deletion of data on hard drives over on security.stackexchange.com. It is a little wider in scope than your question, covering the entire drive, but a range of useful thoughts on the problem list Secure Erase as the recommended method. For flash drives, there are specific problems which come up as well.


1

If you want to be really sure, tar the whole filesystem to another drive, like this: ssh host "tar --one-file-system -jcf - /" > system-root.tar.bz2 Then use shred to wipe the device, and untar the contents back. With shred you can specify the amount of wipes; I would run 0-2 writes with random data and then zero over it. Why just 1-3 writes and not ...


1

Shred will overwrite the file by reading and writing it with new information (random data). Each time it is rewritten, the fylesystem will have to deal with uncompressing it, getting the bytes from shred, compressing them and finally writing them back to the fylesystem. Edit: the shred manpage have some information about compressed filesystem. The problem ...


1

The reason it takes a loong time is that shred is overwriting every bit of the original file and then rewriting with zeros. A single overwrite will do everything you need (unless you have a specific regulatory requirement for multiple overwrites) so checking the file size then copying a file of at least that to each one will overwrite the whole file. If ...


1

Note that erasing single files on modern filesystem (for example NTFS/ext3/ext4) is not guaranteed operation. Only way to securely wipe files is to wipe whole disk. On related news, short article. I would recommend adding disk encryption software (Truecrypt for Windows) to protect files. That way for example temporary files are protected too. As of wiping ...


1

With conventional hard drives, a single wipe with zeros may be enough The 'multiple wipes' method assumes that you're using older drives (with larger magnetic domains). The 'definitive' paper on data destruction by guttmann suggests 35 different patterns - which are effective on different types of drives. Guttmann suggests filling the drive with random ...


1

You can copy rubbish multiple times. for i in `seq 1 35`; do dd if=/dev/urandom of=/dev/sdX done



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