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

[Kay Sievers]

On Wed, Jun 17, 2015 at 2:28 PM, Reindl Harald <h.reindl at thelounge.net> wrote:
>
> Am 17.06.2015 um 14:21 schrieb cee1:
>>
>> 2015-06-17 16:40 GMT+08:00 Reindl Harald <h.reindl at thelounge.net>:
>>>>
>>>> systemd-random-seed.service will load the "seed on disk" to
>>>> /dev/urandom, and save a "seed" to disk when shutdown, right?
>>>>
>>>> The article at http://www.2uo.de/myths-about-urandom/ suggests us
>>>> saving the seed as soon as there is enough entropy(means read from
>>>> /dev/random? if returns, there's enough entropy),
>>>
>>>
>>> well, so you read the seed and inject it to /dev/random followed by read
>>> /dev/random and overwrite the seed for the next boot - don't sounds that
>>> good
>>
>>
>> What I means is:
>> 1. Load a saved seed to /dev/urandom.
>> 2. The service read /dev/random, which will block until kernel thinks
>> there's enough entropy - then the Random Number should be good?
>> 3. Save the random number returned in step 2 on disk
>
>
> oh yeah block at boot sounds what we want.....

The suggestion is reasonable and part of a useful technical discussion.

Your reply is not constructive or funny, and even plain wrong in its
assumptions. Please keep such comments to yourself or you will be
moderated again.

Thanks,
Kay