I have a laptop that I want to sell, but on the hard drive I used to keep sensitive information, like tax records, personal photos, etc. What is the best way of processing this drive to remove all of this, and make it so no one could be able to recover it?
Don't use DBAN if you have a SSD. Instead, use Secure Erase.
1. Secure Erase will only take a few seconds.
2. DBAN is going to shorten the life of the drive.
3. Yes, recovering data that has been overwritten is unlikely. However, DBAN is likely to not write over the data in the first place. It has no control over where the data is written. That's handled by the SSD controller. DBAN will only think it wrote zeros over the entire drive, while not actually doing so.
I don't think only writing zeros is considered safe, I mean it probably is for most purely software based recovery methods but I don't think it is for agencies with money to build the right hardware. Look into DoD 5220.22-M.
for ATA disk drives manufactured after 2001
(over 15 GB) clearing by overwriting the media once is adequate to protect the media from
both keyboard and laboratory attack.
Recovery from an overwritten file has essentially never been done. Or if it has, it has been kept top secret.
There was one study a long time ago where a few bits were recovered with some accuracy with an electron microscope, but it was from a really old hard drive with a much lower density than current ones.
Those overwriting regulations are just in case such technology might get invented in the future.
If it is a Windows machine and you are trying to leave Windows in-place (not recommend) you can at least delete your user account, empty the trash can, and then run a program like SDelete - http://technet.microsoft.com/en-us/sysinternals/bb897443.asp...
shred is a Unix command that can be used to securely delete
files and devices so that they can be recovered only with
great difficulty with specialised hardware, if at all. It
is a part of GNU Core Utilities.
Before you wipe the drive you could do a whole drive encryption with TrueCrypt or BitLocker and then use DBAN for spinning drives or Secure Erase for SSDs.
You issue the Secure Erase command. My SSD is my primary drive running Windows, so when I format, I just boot to PartedMagic on USB. It takes about 5 or 10 seconds for my SSD to format using Secure Erase.
I know, which is also why it's so hard to wipe it. It seems that SSDs are built with self preservation in mind and it'll try its hardest to avoid a write.
It would be nice if you quoted some reputable source or research when making such bold claims.
Who are the people that can recover more than 1 rewrite easily from a modern hard disk drive, do you have any URLs at hand?
You could check Peter Gutmann's research titled "Secure Deletion of Data from Magnetic and Solid-State Memory" [1] from 1996 which is one of the original sources for "35-cycle erase" [2]. In this paper he states that it is possible to recover the data using a specialized microscopy equipment (using Magnetic Force Microscopy or MF Scanning Tunneling Microscopy techniques). These techniques are only applicable for mediums with a much lower magnetic density and much simpler encoding than are used these days (eg. RLL encodings like MFM, PRML, etc.).
How did you arrive at the number 50? In the epilogue of his paper Gutmann states:
In fact performing the full 35-pass overwrite is pointless for any drive since it targets a blend of scenarios involving all types of (normally-used) encoding technology, which covers everything back to 30+-year-old MFM methods (if you don't understand that statement, re-read the paper). If you're using a drive which uses encoding technology X, you only need to perform the passes specific to X, and you never need to perform all 35 passes.
tl;dr: overwriting 35 times is a pointless waste of time and is one of the popular myths that refuses to die. Using shred under GNU/Linux or DBAN to overwrite with some random data is more than sufficient for our purposes.
Use something like DBAN [1] and forget about it.
(Happy to be corrected)
[1]: http://www.dban.org/