Stupid simple Go binary to overwrite block devices and "wipe them clean".
The idea here is that if you want to overwrite your disk with random data,
the /dev/urandom endpoint is pretty slow in supplying enough data quickly.
But because almost any modern computer has some form of hardware acceleration
for the AES algorithm, you can just encrypt a stream of zeroes with a random
key and you'll get pretty decent randomness. The need for 35 Gutman passes is
long gone, so this one pass ought the be enough, usually.
NOTE: This only reliably works on spinning disks, not flash disks like SSDs! Use ATA Secure Erase in that case, which deletes the MEK on self-encrypting drives and renders all data useless instantly. Some harddisks also have instant secure erase (ISE) – you should prefer that.
go get github.com/ansemjo/eraser
eraser { -rand | -zero } [-direct] [-note] blockdev
Use -rand for the encrypted zerostream described above or -zero to just
use zeroes instead.
The -note flag writes a little note with a timestamp to the first 32 bytes
of blockdev after successful deletion. You can then head -1 blockdev and
see when the disk was deleted later.
With -direct the disk is opened with O_DIRECT, which bypasses most caches and gives a more realistic speed.
The progress spinner calculates the estimated remaining time based on the average speed of the bytes written so far, as I've found that the current average speed is a very bad measure for accurate estimations.
I'm not a cryptographer. This is just a small utility I like to use because
I was fed up with copy-pasting a long openssl enc command. Don't trust me
with your data.