[Cryptography] Mac OS 10.7.5 Random Numbers

John Kelsey crypto.jmk at gmail.com
Sat Feb 1 11:01:36 EST 2014


On Feb 1, 2014, at 1:06 AM, Bill Frantz <frantz at pwpconsult.com> wrote:
(quoting from the BSD /dev/random man page)
...
>     Yarrow is a fairly resilient algorithm, and is believed to be resistant to non-root.
>     The quality of its output is however dependent on regular addition of appropriate 
>     entropy. If the SecurityServer system daemon fails for any reason, output quality 
>     will suffer over time without any explicit indication from the random device itself.

This isn't quite right.  Once Yarrow is in a secure state, it will stay there unless the state is compromised.  If there is no more entropy coming in after that, it will never recover.  

> Bill Frantz        | The first thing you need when  | Periwinkle
> (408)356-8506      | using a perimeter defense is a | 16345 Englewood Ave
> www.pwpconsult.com | perimeter.                     | Los Gatos, CA 95032

--John


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