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Date: Sun, 10 Jul 2016 21:29:08 +0200
From: Stephan Mueller <>
To: Shubham Bansal <>
Subject: Re: Looking for something to WORK ON

Am Sonntag, 10. Juli 2016, 22:12:53 CEST schrieb Shubham Bansal:

Hi Shubham,

> Hi Sandy,
> On Wed, Jul 6, 2016 at 8:44 PM, Sandy Harris <> wrote:
> > Shubham Bansal <> wrote:
> > > I want to start with linux kernel development and looking for some
> > 
> > project
> > 
> > > where I can contribute.
> > 
> > Nearly all crypto and the address randomisation that is part of kernel
> > hardening depend on good random numbers, for Linux on the random(4)
> > driver. Getting it initialised early enough & well enough is an
> > extremely tricky problem. Several people have proposed solutions but
> > AFAIK none are complete and it might benefit from having fresh eyes
> > take a look, especially if you have a good background in crypto or
> > math.
> I have a basic understanding of crypto as I just graduated. But it sound
> really interesting to work on. I am happy to work on it if you think it
> would be good, But I must tell you that I have to read a lot for this.
> > Not all discussion is here; other relevant lists include
> > and
> Subscribed.
> > People to
> > look for include the maintainer,, the main person
> > working on the problem here,,
> Should I mail them to get the update and how can I start contributing ?
> > two guys who have
> > proposed drive rewrites that partly solve the problem, me and
> >, and one with a lot of excellent comments,
> >
> Would it be possible to work with you on this ? I would try my best. I
> would need some help from your side though.
> Looking forward to hearing back from you. I would like to get started with
> it soon.

My code is in the kernel at crypto/jitterentropy.c. It is completely 
standalone and does not require anything, provided the intended architecture 
has either random_get_entropy() or get_cycles implemented. I have tested it on 
bare metal without a kernel. Thus, it can be operational as early as you need 

To make it fully standalone, you have to:

- compile jitterentropy.c and the helper functions listed at the top in 
jitterentropy.c and implemented in jitterentropy_kcapi.c (note, 
jent_fips_enabled is not needed for your purpose)

- statically allocate the memory obtained in jent_entropy_collector_alloc

- ensure serialization as necessary

I strongly suggest that you call jent_entropy_init to ensure that the timer 
has a sufficient high resolution before you collect entropy with 

Note, I am currently getting help from a big chip vendor tracking down the 
root cause that beyond the analysis of chapter 6.1 in my report.


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