> Don Davis <[EMAIL PROTECTED]> writes:
> >    perhaps surprisingly, i disagree with the other
> > respondents.  as long as you encrypt or MAC the
> > incoming packets (& their interarrival times),
> > with a closely-guarded secret key, before you
> > stuff the bits into your entropy pool,  then you
> > should do fine.
> 
> Eh?  You should *never* need to encrypt information before shoving
> it in the pool.  If you've got a secret you could use for such
> encryption, shove it in the pool and then forget about it - it will do 
> precisely as much good.

I'm inclined to agree with Don here, from principles of conservative
cryptographic engineering.  By using a keyed one-way function before
adding data to the pool, you add an additional layer of defense
against an attacker guessing the pool contents.

[The /dev/random designs i've played with typically have a "pre" pool
for efficient accumulation of samples at interrupt level or similar
inconvenient times, and a "real" pool, with the encryption/one way
hash occurring when the samples are added to the real pool.]

                                                - Bill




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