securely delete (wipe) a file/partition

Problem

I had a USB stick that I wanted to clean, i.e. even if I lose it, I don’t want anyone to be able to recover the data on it.

Solution

Removing a file with rm or formatting a partition (with gparted for instance) is not enough. There are tools that can restore deleted files. A better way is to overwrite a file/partition repeatedly with random garbage (wipe). And there is still the most secure way: smash your drive with a hammer and pour acid on it :)

shred

Shred can wipe a file or an entire partition. If you shred a partition, all data on it will be lost. If you only want to wipe the free space, you’ll need another tool. Here is how I wiped my USB stick:

# figure out the device reference of the partition:
df -h
# then wipe it:
sudo shred -n 5 -v /dev/XXX

Where -n 5 means we want to overwrite the paprtition 5 times; -v means verbosity; and /dev/XXX is the device reference of the partition.

Credits: http://www.linux.com/archive/feature/52258.

Alternatives

• secure-delete tools (sudo apt-get install secure-delete); more info here
• wipe (sudo apt-get install wipe); more info here
• dban; more info here

The toolset secure-delete comes with four commands:

1. srm (remove files/directories)
2. sdmem (wipe memory)
3. sfill (wipe free space)
4. sswap (wipe swap partition)