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To: Colin Plumb <[EMAIL PROTECTED]>
Cc: [EMAIL PROTECTED], [EMAIL PROTECTED], [EMAIL PROTECTED],
        [EMAIL PROTECTED], [EMAIL PROTECTED]
Subject: Re: Intel announcements at RSA '99 
Date: Tue, 26 Jan 1999 18:17:50 -0500
From: Steve Bellovin <[EMAIL PROTECTED]>
Status: R

Steve Bellovin wrote:
> What I was told at RSA was that the SHA-1 whitening was done by the driver.
> The driver (I think it was the driver, rather than the hardware) also does
> its own quality checks on the hardware RNG.

Ah, good, somebody at Intel gets the point.

>> (I'm also curious what people think is a good rate.  I think we surprised
>> them by saying that one bit per second was adequate.  Anything more can
>> be generated by cryptographic means.)

> I asked about speed; I was told that that isn't public yet.  I do not
> agree that one bit per second is adequate.  Apart from any question of
> the strength of the cryptographic RNG, it means that it would take many
> minutes to have enough entropy for even a single true-random DH exchange.
> Their own goal was "fast enough for IPSEC", which is not that fast, though
> more, I would guess, than your statement.

Yes, this is a number I do know (it came up in the same conversation),
and it's rather a lot more than 1 bit per second. :-)

But I still think that given a reasonable amount of seed material,
I can do cryptographic "reprocessing of spent fuel" basically forever
with good security.  More is nice, but I do think that 1 bit per second
is all that is *necessary* for 95% of the benefit.
-- 
        -Colin

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