On Sun, Aug 27, 2017 at 8:59 PM, Robert Moskowitz <rgm(a)htt-consult.com> wrote:
On 08/27/2017 03:31 PM, Peter Robinson wrote:
>
> On Sun, Aug 27, 2017 at 6:57 PM, Robert Moskowitz <rgm(a)htt-consult.com>
> wrote:
>>
>> I use:
>>
>> cat /proc/sys/kernel/random/entropy_avail
>>
>> To check on the amount of entropy for creating random stuff like keypairs
>> with openssl or random nonces and keys for TLS..
>>
>> I am using a Cubieboad2.
>>
>> With Fedora-Xfce-armhfp-26-1.5-sda.raw.xz I was seeing numbers in the
>> 3,000.
>> I don't have that image running right now to get an actual number.
>>
>> I just built a system with: Fedora-Server-armhfp-26-1.5-sda.raw.xz
>>
>> I am seeing numbers only in the mid 800s:
>>
>> [root@C2 ~]# cat /proc/sys/kernel/random/entropy_avail
>> 866
>> [root@C2 ~]# cat /proc/sys/kernel/random/entropy_avail
>> 803
>> [root@C2 ~]# cat /proc/sys/kernel/random/entropy_avail
>> 828
>>
>>
>> What is different between these two images? It is the same Cubieboard.
>
> Different images have different services enabled by default, is
> rng-tools intsalled by default on server image?
Just checked and
Package rng-tools-5-9.fc26.armv7hl is already installed
And after running dnf, entropy dropped to 324....
>
>> I have also installed rng-tools with some success, but not as much as
>> haveged.
>
> There's a quality difference between HW rng vs haveged which provides
> entropy but might not be as random as a proper HW rng
>
I could boot up the workstation Xfce image I have, but I was kind of hoping
there was some knowledge here on differences.
Other than workstation running something like haveged, what else could be
the source of the entropy difference?
Different services consuming the available entropy