How to verify that a shredding has been done?
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I want to test a magnetic disk to be (quite) sure a shredding has been done.
- Hypo1 : a
shred -n 3was applyed - Hypo2 : a
shred -n 1was applyed - Hypo3 : no shred was applyed
How to test in which state the disk is?
hard-drive data-recovery shred
asked Feb 6 at 13:12
SandburgSandburg
337
add a comment |
0
I want to test a magnetic disk to be (quite) sure a shredding has been done.
- Hypo1 : a
shred -n 3was applyed - Hypo2 : a
shred -n 1was applyed - Hypo3 : no shred was applyed
How to test in which state the disk is?
hard-drive data-recovery shred
asked Feb 6 at 13:12
SandburgSandburg
337
What kind of disk is it? Flash memory & SSD's don't always keep data in the same place, and they can "hide" sectors in normally inaccessible areas, so truly erasing all data could be impossible (unless you use Mjölnir). Anyway, did you copy a few sectors/files before shredding, then compare them after shredding?
– Xen2050
Feb 7 at 10:28
Hi @Wen2050 . My subject is about magnetic disks, I will edit my qst. I knew flash based storage have strange behaviour making erasing complicated. (sadly, my best source of info is this hacker book in French guide.boum.org/tomes/1_hors_connexions/unepage/#index77h3 )
– Sandburg
Feb 7 at 10:34
add a comment |
0
0
0
I want to test a magnetic disk to be (quite) sure a shredding has been done.
- Hypo1 : a
shred -n 3was applyed - Hypo2 : a
shred -n 1was applyed - Hypo3 : no shred was applyed
How to test in which state the disk is?
hard-drive data-recovery shred
asked Feb 6 at 13:12
SandburgSandburg
337
I want to test a magnetic disk to be (quite) sure a shredding has been done.
- Hypo1 : a
shred -n 3was applyed - Hypo2 : a
shred -n 1was applyed - Hypo3 : no shred was applyed
How to test in which state the disk is?
hard-drive data-recovery shred
hard-drive data-recovery shred
asked Feb 6 at 13:12
SandburgSandburg
337
asked Feb 6 at 13:12
SandburgSandburg
337
edited Feb 7 at 10:34
Sandburg
asked Feb 6 at 13:12
SandburgSandburg
337
asked Feb 6 at 13:12
SandburgSandburg
337
asked Feb 6 at 13:12
SandburgSandburg
337
337
What kind of disk is it? Flash memory & SSD's don't always keep data in the same place, and they can "hide" sectors in normally inaccessible areas, so truly erasing all data could be impossible (unless you use Mjölnir). Anyway, did you copy a few sectors/files before shredding, then compare them after shredding?
– Xen2050
Feb 7 at 10:28
Hi @Wen2050 . My subject is about magnetic disks, I will edit my qst. I knew flash based storage have strange behaviour making erasing complicated. (sadly, my best source of info is this hacker book in French guide.boum.org/tomes/1_hors_connexions/unepage/#index77h3 )
– Sandburg
Feb 7 at 10:34
add a comment |
What kind of disk is it? Flash memory & SSD's don't always keep data in the same place, and they can "hide" sectors in normally inaccessible areas, so truly erasing all data could be impossible (unless you use Mjölnir). Anyway, did you copy a few sectors/files before shredding, then compare them after shredding?
– Xen2050
Feb 7 at 10:28
Hi @Wen2050 . My subject is about magnetic disks, I will edit my qst. I knew flash based storage have strange behaviour making erasing complicated. (sadly, my best source of info is this hacker book in French guide.boum.org/tomes/1_hors_connexions/unepage/#index77h3 )
– Sandburg
Feb 7 at 10:34
What kind of disk is it? Flash memory & SSD's don't always keep data in the same place, and they can "hide" sectors in normally inaccessible areas, so truly erasing all data could be impossible (unless you use Mjölnir). Anyway, did you copy a few sectors/files before shredding, then compare them after shredding?
– Xen2050
Feb 7 at 10:28
What kind of disk is it? Flash memory & SSD's don't always keep data in the same place, and they can "hide" sectors in normally inaccessible areas, so truly erasing all data could be impossible (unless you use Mjölnir). Anyway, did you copy a few sectors/files before shredding, then compare them after shredding?
– Xen2050
Feb 7 at 10:28
Hi @Wen2050 . My subject is about magnetic disks, I will edit my qst. I knew flash based storage have strange behaviour making erasing complicated. (sadly, my best source of info is this hacker book in French guide.boum.org/tomes/1_hors_connexions/unepage/#index77h3 )
– Sandburg
Feb 7 at 10:34
Hi @Wen2050 . My subject is about magnetic disks, I will edit my qst. I knew flash based storage have strange behaviour making erasing complicated. (sadly, my best source of info is this hacker book in French guide.boum.org/tomes/1_hors_connexions/unepage/#index77h3 )
– Sandburg
Feb 7 at 10:34
add a comment |
1 Answer
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There's no difference between shred -1 and -3 in a practical sense. You're just running more than one pass of the wipe
A 'simple' way to check if a disk has been properly wiped is to try recovery with common data recovery or forensic tools to see if any data is there. I'd go with testdisk since it's pretty common but feel free to throw whatever you want at it
answered Feb 6 at 13:23
Journeyman Geek♦Journeyman Geek
113k44218372
There is a difference between shred 1 and shred 3, but that was not the important point of my question. Thank you for your answer. When the computer rewrites 1 over 0, it gives 0.95 instead and when rewriting 1 over 1, it gives rather 1.0555... (Source cs.auckland.ac.nz/~pgut001/pubs/secure_del.html)
– Sandburg
Feb 6 at 13:30
...imo. not really. You just run more passes and feel more smug about it. The guttman paper was written with much older drives with bigger domains
– Journeyman Geek♦
Feb 6 at 13:33
@Sandburg The only different thing is the algorithm used for the wipe. In theory you can reconstruct data given that you also know the algorithm. But you just can't differentiate beteween shred 1 and shred n. That's like erasing a file_a, then filling the space with more files, then delete everything and try to recover file_a. As said by Journeyman Geek, you can check the data with tools like "R-studio", it can take a long time, and see if you can recover any.
– dmb
Feb 6 at 13:40
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
3
There's no difference between shred -1 and -3 in a practical sense. You're just running more than one pass of the wipe
A 'simple' way to check if a disk has been properly wiped is to try recovery with common data recovery or forensic tools to see if any data is there. I'd go with testdisk since it's pretty common but feel free to throw whatever you want at it
answered Feb 6 at 13:23
Journeyman Geek♦Journeyman Geek
113k44218372
There is a difference between shred 1 and shred 3, but that was not the important point of my question. Thank you for your answer. When the computer rewrites 1 over 0, it gives 0.95 instead and when rewriting 1 over 1, it gives rather 1.0555... (Source cs.auckland.ac.nz/~pgut001/pubs/secure_del.html)
– Sandburg
Feb 6 at 13:30
...imo. not really. You just run more passes and feel more smug about it. The guttman paper was written with much older drives with bigger domains
– Journeyman Geek♦
Feb 6 at 13:33
@Sandburg The only different thing is the algorithm used for the wipe. In theory you can reconstruct data given that you also know the algorithm. But you just can't differentiate beteween shred 1 and shred n. That's like erasing a file_a, then filling the space with more files, then delete everything and try to recover file_a. As said by Journeyman Geek, you can check the data with tools like "R-studio", it can take a long time, and see if you can recover any.
– dmb
Feb 6 at 13:40
add a comment |
3
There's no difference between shred -1 and -3 in a practical sense. You're just running more than one pass of the wipe
A 'simple' way to check if a disk has been properly wiped is to try recovery with common data recovery or forensic tools to see if any data is there. I'd go with testdisk since it's pretty common but feel free to throw whatever you want at it
answered Feb 6 at 13:23
Journeyman Geek♦Journeyman Geek
113k44218372
There is a difference between shred 1 and shred 3, but that was not the important point of my question. Thank you for your answer. When the computer rewrites 1 over 0, it gives 0.95 instead and when rewriting 1 over 1, it gives rather 1.0555... (Source cs.auckland.ac.nz/~pgut001/pubs/secure_del.html)
– Sandburg
Feb 6 at 13:30
...imo. not really. You just run more passes and feel more smug about it. The guttman paper was written with much older drives with bigger domains
– Journeyman Geek♦
Feb 6 at 13:33
@Sandburg The only different thing is the algorithm used for the wipe. In theory you can reconstruct data given that you also know the algorithm. But you just can't differentiate beteween shred 1 and shred n. That's like erasing a file_a, then filling the space with more files, then delete everything and try to recover file_a. As said by Journeyman Geek, you can check the data with tools like "R-studio", it can take a long time, and see if you can recover any.
– dmb
Feb 6 at 13:40
add a comment |
3
3
3
There's no difference between shred -1 and -3 in a practical sense. You're just running more than one pass of the wipe
A 'simple' way to check if a disk has been properly wiped is to try recovery with common data recovery or forensic tools to see if any data is there. I'd go with testdisk since it's pretty common but feel free to throw whatever you want at it
answered Feb 6 at 13:23
Journeyman Geek♦Journeyman Geek
113k44218372
There's no difference between shred -1 and -3 in a practical sense. You're just running more than one pass of the wipe
A 'simple' way to check if a disk has been properly wiped is to try recovery with common data recovery or forensic tools to see if any data is there. I'd go with testdisk since it's pretty common but feel free to throw whatever you want at it
answered Feb 6 at 13:23
Journeyman Geek♦Journeyman Geek
113k44218372
answered Feb 6 at 13:23
Journeyman Geek♦Journeyman Geek
113k44218372
answered Feb 6 at 13:23
Journeyman Geek♦Journeyman Geek
113k44218372
answered Feb 6 at 13:23
Journeyman Geek♦Journeyman Geek
113k44218372
113k44218372
There is a difference between shred 1 and shred 3, but that was not the important point of my question. Thank you for your answer. When the computer rewrites 1 over 0, it gives 0.95 instead and when rewriting 1 over 1, it gives rather 1.0555... (Source cs.auckland.ac.nz/~pgut001/pubs/secure_del.html)
– Sandburg
Feb 6 at 13:30
...imo. not really. You just run more passes and feel more smug about it. The guttman paper was written with much older drives with bigger domains
– Journeyman Geek♦
Feb 6 at 13:33
@Sandburg The only different thing is the algorithm used for the wipe. In theory you can reconstruct data given that you also know the algorithm. But you just can't differentiate beteween shred 1 and shred n. That's like erasing a file_a, then filling the space with more files, then delete everything and try to recover file_a. As said by Journeyman Geek, you can check the data with tools like "R-studio", it can take a long time, and see if you can recover any.
– dmb
Feb 6 at 13:40
add a comment |
There is a difference between shred 1 and shred 3, but that was not the important point of my question. Thank you for your answer. When the computer rewrites 1 over 0, it gives 0.95 instead and when rewriting 1 over 1, it gives rather 1.0555... (Source cs.auckland.ac.nz/~pgut001/pubs/secure_del.html)
– Sandburg
Feb 6 at 13:30
...imo. not really. You just run more passes and feel more smug about it. The guttman paper was written with much older drives with bigger domains
– Journeyman Geek♦
Feb 6 at 13:33
@Sandburg The only different thing is the algorithm used for the wipe. In theory you can reconstruct data given that you also know the algorithm. But you just can't differentiate beteween shred 1 and shred n. That's like erasing a file_a, then filling the space with more files, then delete everything and try to recover file_a. As said by Journeyman Geek, you can check the data with tools like "R-studio", it can take a long time, and see if you can recover any.
– dmb
Feb 6 at 13:40
There is a difference between shred 1 and shred 3, but that was not the important point of my question. Thank you for your answer. When the computer rewrites 1 over 0, it gives 0.95 instead and when rewriting 1 over 1, it gives rather 1.0555... (Source cs.auckland.ac.nz/~pgut001/pubs/secure_del.html)
– Sandburg
Feb 6 at 13:30
There is a difference between shred 1 and shred 3, but that was not the important point of my question. Thank you for your answer. When the computer rewrites 1 over 0, it gives 0.95 instead and when rewriting 1 over 1, it gives rather 1.0555... (Source cs.auckland.ac.nz/~pgut001/pubs/secure_del.html)
– Sandburg
Feb 6 at 13:30
...imo. not really. You just run more passes and feel more smug about it. The guttman paper was written with much older drives with bigger domains
– Journeyman Geek♦
Feb 6 at 13:33
...imo. not really. You just run more passes and feel more smug about it. The guttman paper was written with much older drives with bigger domains
– Journeyman Geek♦
Feb 6 at 13:33
@Sandburg The only different thing is the algorithm used for the wipe. In theory you can reconstruct data given that you also know the algorithm. But you just can't differentiate beteween shred 1 and shred n. That's like erasing a file_a, then filling the space with more files, then delete everything and try to recover file_a. As said by Journeyman Geek, you can check the data with tools like "R-studio", it can take a long time, and see if you can recover any.
– dmb
Feb 6 at 13:40
@Sandburg The only different thing is the algorithm used for the wipe. In theory you can reconstruct data given that you also know the algorithm. But you just can't differentiate beteween shred 1 and shred n. That's like erasing a file_a, then filling the space with more files, then delete everything and try to recover file_a. As said by Journeyman Geek, you can check the data with tools like "R-studio", it can take a long time, and see if you can recover any.
– dmb
Feb 6 at 13:40
add a comment |
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What kind of disk is it? Flash memory & SSD's don't always keep data in the same place, and they can "hide" sectors in normally inaccessible areas, so truly erasing all data could be impossible (unless you use Mjölnir). Anyway, did you copy a few sectors/files before shredding, then compare them after shredding?
– Xen2050
Feb 7 at 10:28
Hi @Wen2050 . My subject is about magnetic disks, I will edit my qst. I knew flash based storage have strange behaviour making erasing complicated. (sadly, my best source of info is this hacker book in French guide.boum.org/tomes/1_hors_connexions/unepage/#index77h3 )
– Sandburg
Feb 7 at 10:34