/dev/random question

[Per olof Ljungmark]

Roland Smith wrote:
> On Thu, Sep 13, 2007 at 05:31:55PM +0100, RW wrote:
>> On Thu, 13 Sep 2007 17:36:30 +0200
>> Roland Smith <rsmith at xs4all.nl> wrote:
>>
>>> On Thu, Sep 13, 2007 at 04:56:26PM +0200, Per olof Ljungmark wrote:
>>>> Hi,
>>>>
>>>> Could someone on the list point me to a document that explains the 
>>>> functionality of /dev/random in FreeBSD in a little more depth than
>>>> the man page? In other OS's I've looked at random and urandom are
>>>> different, here it's a symlink (talking about RELENG-6 onwards).
>>>  
>>> FreeBSD uses the yarrow algorithm, as mentioned in random(4). See 
>>> http://en.wikipedia.org/wiki/Yarrow_algorithm
>>> http://www.schneier.com/yarrow.html
>> Yarrow is reseeded with interrupt entropy, and is supposedly good
>> enough not to require the amount of entropy to be tracked.
>> So /dev/random need not block, and there's no need for a separate
>> non-blocking device.  
> 
> On the website it says that the original yarrow algorithm is no longer
> supported. It seems to have been replaced by the fortuna algorithm.
> 
> I can't see from the source if /usr/src/sys/dev/random/yarrow.* use the
> original yarrow algorithm, or the improved yarrow-160 aka fortuna. The use of
> crypto/rijndael/rijndael-api-fst.h and crypto/sha2/sha2.h seem to
> indicate the latter though.

Should I conclude then that randomness is sufficient and performance is 
a non-issue?