[systemd-devel] Why we need to read/save random seed?

[Mantas Mikulėnas]

On Sun, Jun 14, 2015 at 4:21 PM, cee1 <fykcee1 at gmail.com> wrote:

> Hi all,
>
> Why we need to read/save random seed? Can it be read from /dev/random each
> time?


Well, that would sorta defeat the point.

The random seed isn't for systemd's use. On boot, it is *written to*
/dev/random,
not read from it. Early during boot, the system has very little entropy
available from other sources, so it is common to save some random data from
last boot and provide it to the PRNG later.

-- 
Mantas Mikulėnas <grawity at gmail.com>
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