Re: Shredding a removable drive (OT)

[Roberto Ragusa]

On 1/30/19 12:48 AM, Gordon Messmer wrote:
> Both the filesystem and your data are encrypted when using dm-crypt (whether you use LUKS or not).  However, creating a dm-crypt device doesn't modify the pre-existing data.  It only writes encrypted data to the disk when data is written to the virtual device.
>
> Does that make sense?

Yes, and the reason for doing this is that encrypting some zeros can be faster than reading from /dev/urandom.
I know for sure that /dev/urandom is (or was) not always able to saturate the speed of a disk (or SSD), while
dmcrypt with modern hardware (AES instructions in the CPU) is always fast enough.

Regards.