[DragonFlyBSD - Bug #1689] IBAA recommendation

[bugtracker-admin at leaf.dragonflybsd.org]

Issue #1689 has been updated by robin.carey1.


Dear Alex,

You seem to be blissfully unaware that it already has "been tweaked" (to
use your wording).

On 19 January 2015 at 14:24, <bugtracker-admin at leaf.dragonflybsd.org> wrote:

> Issue #1689 has been updated by alexh.
>
>
> We should stay away from non-reviewed work in this area. Bob Jenkins'
> IBAA/ISAAC implementations have been used and reviewed a fair number of
> times, unlike rcarey's work.
>
> The main reason we still have IBAA around is as a sort of safety net
> against any potential (implementation) bugs in the new CSPRNG. As such, it
> sounds like a pretty bad idea to try and tweak it like this.
>
> IMO this should be closed, but I'll leave it up to you.
>
> ----------------------------------------
> Bug #1689: IBAA recommendation
> http://bugs.dragonflybsd.org/issues/1689#change-12535
>
> * Author: robin.carey1
> * Status: Feedback
> * Priority: Low
> * Assignee:
> * Category: Crypto
> * Target version: 4.2.x
> ----------------------------------------
> Dear DragonFlyBSD bugs.
>
> DragonFly uses Bob Jenkins' IBAA CSPRNG for /dev/random.
>
> I have been doing some work on this CSPRNG, which is available from:
>
> http://www.leopard.uk.com/IBAA64
>
> I have two recommendations to make with regard to the IBAA CSPRNG which is
> used in DragonFly:
>
> (1) Use my rounded up BETA=32/SHIFT=20 values as opposed to the original
> SHIFT=19 value in the
> original IBAA CSPRNG/algorithm (details available from above URL)
>
> and
>
> (2) Use a 32-bit counter. This is a minor modification, which gurantees no
> bad states (an initial state of all zeroes
>      maps back to an internal state of all zeroes after 256 iterations),
> and
> also guarantees a cycle length of at least
>      2^32. Details on how to implement the counter are available from the
> above URL. It's a minor modification which
>      has minimal performance impact.
> Also, a 64-bit version of IBAA is available from the above URL. Matthew
> Dillon seemed to be interested in that, with
> regard to the 64-bit x86-64 port of DragonFly (but I haven't heard back
> from
> him about that).
>
> ---Files--------------------------------
> unnamed (1.4 KB)
>
>
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-- 
Sincerely,

Robin Carey BSc

----------------------------------------
Bug #1689: IBAA recommendation
http://bugs.dragonflybsd.org/issues/1689#change-12538

* Author: robin.carey1
* Status: Feedback
* Priority: Low
* Assignee: 
* Category: Crypto
* Target version: 4.2.x
----------------------------------------
Dear DragonFlyBSD bugs.

DragonFly uses Bob Jenkins' IBAA CSPRNG for /dev/random.

I have been doing some work on this CSPRNG, which is available from:

http://www.leopard.uk.com/IBAA64

I have two recommendations to make with regard to the IBAA CSPRNG which is
used in DragonFly:

(1) Use my rounded up BETA=32/SHIFT=20 values as opposed to the original
SHIFT=19 value in the
original IBAA CSPRNG/algorithm (details available from above URL)

and

(2) Use a 32-bit counter. This is a minor modification, which gurantees no
bad states (an initial state of all zeroes
     maps back to an internal state of all zeroes after 256 iterations), and
also guarantees a cycle length of at least
     2^32. Details on how to implement the counter are available from the
above URL. It's a minor modification which
     has minimal performance impact.
Also, a 64-bit version of IBAA is available from the above URL. Matthew
Dillon seemed to be interested in that, with
regard to the 64-bit x86-64 port of DragonFly (but I haven't heard back from
him about that).

---Files--------------------------------
unnamed (1.4 KB)


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