[Cryptography] [RNG] on RNGs, VM state, rollback, etc.

[Peter Saint-Andre]

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On 10/24/13 10:55 AM, Jerry Leichter wrote:
> On Oct 24, 2013, at 10:59 AM, John Kelsey <crypto.jmk at gmail.com>
> wrote:
>> We seem to be seeing a move toward commonly-used CPUs including
>> hardware entropy sources.  With those, we're in a much better
>> position.  There's always the possibility that the entropy source
>> was cooked or flawed, but that's something you can engineer your
>> way around reasonably well.
>> 
>> Suppose you have a cryptographic PRNG that you initialize with a
>> seed like this:
>> 
>> a.  Get 256 bits of entropy from the OS. b.  Get 256 bits of
>> entropy from the hardware entropy source. c.  Ping several hosts
>> on the internet and measure the response time, and fold that into
>> your seed. d.  Fold your ethernet address, IP address, and serial
>> number into the seed. e.  Fold the installed-at-birth secret 128
>> bit value from your device into the seed.
> As long as you're at it, ask a whole bunch of hosts, close and far,
> for 256 random bits from their own generators.  If even a single
> one of the response slips by an attacker, he's lost.

By 'hosts' do you mean do you mean servers, or also endpoints? If the
latter, I see interesting possibilities for a "network of friends"
system of the kind Perry sketched out here a month or two ago.

Peter

- -- 
Peter Saint-Andre
https://stpeter.im/


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