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Bug #1689

closed

IBAA recommendation

Added by robin.carey1 over 14 years ago. Updated over 9 years ago.

Status:
Closed
Priority:
Low
Assignee:
-
Category:
Crypto
Target version:
Start date:
Due date:
% Done:

0%

Estimated time:

Description

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).


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unnamed (1.4 KB) unnamed robin.carey1, 03/07/2010 06:42 PM
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