Red Hat Enterprise Linux 9 Essentials Book now available.
Purchase a copy of Red Hat Enterprise Linux 9 (RHEL 9) Essentials
Red Hat Enterprise Linux 9 Essentials Print and eBook (PDF) editions contain 34 chapters and 298 pages
28.4.2. Optional: Fill the device with random data
Filling <device> (eg: /dev/sda3) with random data before encrypting it greatly increases the strength of the encryption. The downside is that it can take a very long time.
Warning
The commands below will destroy any existing data on the device.
The best way, which provides high quality random data but takes a long time (several minutes per gigabyte on most systems):
dd if=/dev/urandom of=<device>
Fastest way, which provides lower quality random data: