[ale] RasPI random numbers

Alex Carver agcarver+ale at acarver.net
Thu Dec 3 16:50:44 EST 2015


It's already been done for the Pi's hardware RNG:

http://scruss.com/blog/2013/06/07/well-that-was-unexpected-the-raspberry-pis-hardware-random-number-generator/

Plus rng-tools runs FIPS tests every so often to make sure the RNG is
working.



On 2015-12-03 12:18, Chris Fowler wrote:
> Write a program that generates man random numbers from 0-1. 0 is black pixel and 1 is white. Write a large XPM image with that. 
> When you are done look at the image. Do you see any patterns? 
> 
> I did that with an Arduino a few years back when I was playing with one and my daughter asked if she could stay up later. I quickly wrote a program that would blink a LED from fast to slow and then off for no and on for yes. If went off, she went to bed. I then thought "how fair was it?" 
> 
> There are also a test suite you can run against numbers it generates to test randomness. 
> 
> There are issues with getting enough entropy for hostapd. It would complain about this. I loaded haveged and that solved that. Would that solve the ssh key issue? 
> 
>> From: "Alex Carver" <agcarver+ale at acarver.net>
>> To: ale at ale.org
>> Sent: Thursday, December 3, 2015 10:53:11 AM
>> Subject: Re: [ale] RasPI random numbers
> 
>> On 2015-12-03 04:51, Boris Borisov wrote:
>>> http://www.theregister.co.uk/2015/12/02/raspberry_pi_weak_ssh_keys/
> 
>>> some /dev/urandom stuff here:
> 
>>> http://www.2uo.de/myths-about-urandom/
> 
>> Good thing I'm still on wheezy I suppose. For some reason it managed to
>> seed at start. I wonder how that got dropped in the transition.
> 
>> Strangely, though, /dev/urandom by default is not fully reseeded when
>> the Pi is being used in a server mode and no real mention of that is
>> made. The entropy stays very low. I had to install rng-tools to have
>> the hardware RNG hooked to /dev/urandom to boost the entropy while running.
> 
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> 
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