I actually had to deal with this several months ago, when one of my Seagate Barracudas died. I hadn't bothered with any encryption, and I didn't feel comfortable RMAing a drive with other people's data still on it. I ended up just keeping the drive and buying a replacement out of pocket. That said, I was almost certainly just being paranoid. You probably shouldn't worry, for the following reasons:
- Western Digital isn't a sixteen year old at Best Buy. They are real professionals, and a major part of being professional is "don't do shit that will obviously piss off your customers, especially when there is no clear benefit to doing so." They have no interest in seeing your data, and they're probably to busy to deal with it anyway, since they're a high-volume manufacturer in a cutthroat market.
- Related to the previous point, it would destroy Western Digital's reputation if they got caught snooping on customers. Once again, they're professionals, and I'm sure they've thought of this. Securing customer data is a fairly obvious precaution for them to take.
- I have heard numerous stories of data being lost by mouth-breathing office workers forgetting their laptops. I have never heard of data being lost as a result of an RMA process with a reputable manufacturer.
- If the drive can't be read via software, then the only way to get data off it would be to disassemble the hardware. This tends to be ridiculously expensive (many times the cost of the drive), and I seriously doubt WD wants to pay for this every time they get a drive RMAed.
If you're still worried, I suggest you get a really strong magnet (like neodymium) and manually degauss the drive. If you do that,
no one will be reading your data without busting out an MRI.
- Data can be recovered from pre-existing partitons even after a fresh format.
True, at least if you do a quick format. Reiser FS (a Linux filesystem named after famed spousal murderer Hans Reiser) actually had the hilarious problem that
files could remain on the filesystem even after a format, meaning for instance that a particularly nasty virus could infect a partition in such a way that not even an ordinary reformat is guaranteed to get rid of it.
- Passing a magnet over the hard drive is not enough. A regular consumer can't buy a magnet strong enough to truly erase a hard drive and make it 100% irrecoverabe.
They use neodymium magnets in hard drives. You can buy those with a little effort, and evidently they are strong enough to erase hard drives, because that's how hard drives work. I have no idea if the data would be 100% unrecoverable, though.
- Data can be recovered from hard drives where the even the DoD 5220.22-M data wiping algorithm was used.
That's contrary to what I've heard. Supposedly, even a single overwrite with random data will make hard drives unrecoverable even with a magnetic resonance imager. And
according to Wikipedia, the NIST agrees. (Caveat: most drives have extra sectors that they use in case existing sectors go bad. If you write confidential data to a sector, and then that sector goes bad, you will not be able to overwrite that data by ordinary means, although a computer forensics kit or MRI might be able to read it.)
- Data can recovered from hard drives burned in a fire.
Depends on the temperature. A hard drive heated above its
Curie point for any significant length of time will be 100% unrecoverable.
