Question about writing zeros to a hard drive.

[ddeder]

I have a Western Digital hard drive that contains personal info that I am about to give away. I understand that just formatting the drive does not actually erase the data. I intend to use Western Digitals software to write zeros to the drive. Once this has been done, is it virtually impossible for data to be recovered from this hard drive? After all if every bit is set to zero, how can the data be recovered? If it is possible to recover data, am I right to conclude that it would be EXTREMELY costly and difficult to do so?

I know there are a lot of utilities out there that will securely erase a hard drive with random zeros and ones. I do not care to hear about these. I just want to know how difficult it would be to recover data from a WD or Maxtor hard drive that has been zeroed by the manufacturers software.

Thanks.

 

[mechBgon]

You want DBAN. I don't think your zero-fill is going to guarantee much.

 

[kallen]

zero filling will probably be just fine. I know some people like to theorize on how it might be possible to recreate the data, but i don't think anyone has actually done it

 

[SexyK]

Unless the person you're giving the drive too wants to spend a lot of money finding out what was on your drive, just zeroing the drive will be fine. It is technically possible to recover the data if you've only zeroed it one time, but, as you say in your post, it will be extremely costly and time consuming.

 

[Markbnj]

cipher /W:c:

Included with Windows XP. Writes random data to all the empty space (it's all empty after a format, essentially) in several passes.

 

[kallen]

Originally posted by: SexyK
Unless the person you're giving the drive too wants to spend a lot of money finding out what was on your drive, just zeroing the drive will be fine. It is technically possible to recover the data if you've only zeroed it one time, but, as you say in your post, it will be extremely costly and time consuming.

You say it's possible, do you have a link to source that has done it?

 

[thorin]

DBAN is a good way to go. It's compliant with various Gov't requirements for overwriting data on drives.

Canadian Gov't "Hard Drive Secure Information Removal and Destruction Guidelines " can be found here > http://www.rcmp-grc.gc.ca/tsb/pubs/it_sec/index_e.htm
Canadian Gov't "Clearing and Declassifying Electronic Data Storage Devices" can be found here > http://www.cse-cst.gc.ca/publi...ubs/itsg/itsg06-e.html

I'm sure there are similar US Gov't publications as well. Basically if boils down to this; if the information is very important to you and you think other parties will be interested in attaining it then a verifiable triple overwrite is what you should use (all zeros, then all ones, then a verifiable pattern). If the information is important to you but other parties are not likely to expend time/resources on it then a single pass it likely sufficient.

 

[Zepper]

DBAN used to come with Eraser (nice for truly getting rid of individual files or groups of files), now you have to get them separately. I DL all my utilities like that via http://www.MajorGeeks.com .

.bh.

 

[piasabird]

The USA had a policy for DOD (Dept of Defense) Where the data should be overwritten 7 times.

http://www.killdisk.com/

Might try this product. There is a free download version and a more expensive version. The free download writes zero to all locations on the drive. The more expensive versions write random charcters and overwrites multiple times. Even if you delete all your files the data is still there. The free space on your drive is often used to store data temporarily, even when using with swap space.

This site also has recovery programs.

Might be even safer if you could encrypt the data and then erase it.

I have heard that writing zeros to a hard drive is also a good way of conditioning a hard drive. In its own way it tests every location on the drive.

 

[Zepper]

Eraser and DBAN can be set to do a lot more than DoD acceptable, but it can take forever if you do and probably isn't necessary in any case. As noted above, most end users aren't going to have the tools or patience to even get past a zero-fill (assuming that really is possible)

.bh.

 

[piasabird]

The drive manufacturer usually has a zero fill utility. Normally it can also erase the part of the drive that stores the MBR block. I have done this for brand new drives because it tests all the drive storage locations. It did not seem to take that long. Faster than a Windows Install. Maxtor has some utilities that are rather fast.