Data Destruction

This page is a general introduction to data destruction; for specific information on procedure, see Data Destruction HOWTO. =How is data stored on computers=

When you turn a computer off, it forgets everything that's not written down. Computers write to a "storage device" or "block device". This can be a hard disk, and SSD, flash memory, even a floppy disk. The data is stored in a logical organization scheme called a Filesystem. Writing a new filesystem to the device or medium makes the old data inaccessible- but the old data is still there, and a determined person can find it.

We want to get rid of this old data, and that means writing new data over it, or *overwriting* as it's called. The old data needs to be overwritten several times with highly entropic patterns in order to best obscure the old data.

=Risks of having data stolen=


 * 1) Identity theft
 * 2) Monetary loss
 * 3) Public embarrassment
 * 4) Criminal prosecution

=How to protect your data while in use via encryption=

App encryption
GPG / Seahorse for general on-the-fly encryption / decryption of data, signing and verification, key management

CryptoCat / OTR for encrypted or anonymized chat

Full disk encryption

 * 1) LUKS
 * 2) TrueCrypt
 * 3) ecryptfs

=What to do before handing your hard drive to a recycler=

If you don't trust your recycler to properly destroy the data on the device, then you will need to do it yourself. See:
 * 1) dban.org
 * 2) https://www.gnu.org/software/coreutils/manual/html_node/shred-invocation.html

Alternatively, you can physically destroy the drive platters. These are the spinning disks inside the hard drive. This might sound like a good idea, but don't try it at home! The platters must be broken and their coating abraded to be certain of data destruction. This is a process that will involve small sharp pieces of metal in flight, and which might release toxic chemicals. Be careful.

What NOT to do
To a certain sort of person, this sounds like a good idea. Given a large enough electromagnet the results can be pretty impressive. Wear goggles. However, while this procedure ruins the hard disk (and potentially other devices in the vicinity or with which the afflicted HDD is stored) it does not destroy the data. The device can be dismantled and the data read.
 * 1) Don't zap your hard drive with a big electromagnet.