From: praxeology_guy <praxeology_guy@protonmail•com>
To: Daniele Pinna <daniele.pinna@gmail•com>
Cc: Bitcoin Dev <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] BIP proposal: Inhibiting a covert attack on the Bitcoin POW function
Date: Fri, 07 Apr 2017 04:08:10 -0400 [thread overview]
Message-ID: <ISkKlFVqjCYz15w_LEBWha85F2BxFQqO_gJyu8UjehKXgua22inacV7RSMNpg_djX8zyTFJC5muZ7CSShbFp14t5y8YOMVwTwcnLGDr_vFo=@protonmail.com> (raw)
In-Reply-To: <CAEgR2PHPvhT8sPJAshp3UMRWLxc4fNb=Vdke0NQpB+i=SCDaDg@mail.gmail.com>
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Daniele Pinna,
Can you please not forget to supply us more details on the claims made regarding the reverse engineering of the Asic chip?
gmaxwell told me that back even in S7 chips its possible to set the SHA256 midstate/IV instead of just resetting it to the standard SHA256 IV. This essentially allows you to re-use midstates, which is one of the key necessary features for the ASICBOOST optimization to work. From the chip's perspective there is not much difference between the covert and overt optimization methods, particularly given that the whole IV/midstate vector can be set.
The covert method just requires more work than the overt method:. overt you just permutate the version bits, vs the covert one requires you find partial hash collisions of the tx merkle root. The extra work to find the partial tx merkle root hash collisions could be done at different stages in the mining system... some speculate that it could be done in the miner's FPGA.
Not sure how exactly gmaxwell (or his friend) did it. I don't currently own any mining hardware nor the time to do it myself.
Cheers,
Praxeology Guy
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next prev parent reply other threads:[~2017-04-07 8:08 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-07 1:34 Daniele Pinna
2017-04-07 6:46 ` Emilian Ursu
2017-04-07 7:44 ` Alex Mizrahi
2017-04-07 8:08 ` praxeology_guy [this message]
-- strict thread matches above, loose matches on Subject: below --
2017-04-06 4:49 Raystonn .
2017-04-06 7:47 ` praxeology_guy
2017-04-06 12:13 ` David Vorick
2017-04-06 4:47 Oliver Petruzel
2017-04-05 21:37 Gregory Maxwell
2017-04-05 23:05 ` theymos
2017-04-06 0:17 ` Gregory Maxwell
2017-04-06 0:39 ` Joseph Poon
2017-04-06 0:40 ` Joseph Poon
2017-04-06 1:32 ` Gregory Maxwell
2017-04-06 2:09 ` Joseph Poon
2017-04-05 23:25 ` Anthony Towns
2017-04-05 23:42 ` Joseph Poon
2017-04-06 2:10 ` Jonathan Toomim
2017-04-06 20:21 ` Jared Lee Richardson
2017-04-06 2:31 ` Peter Todd
2017-04-06 2:39 ` Bram Cohen
2017-04-06 2:49 ` Peter Todd
2017-04-06 3:11 ` Erik Aronesty
2017-04-06 3:23 ` Peter Todd
2017-04-06 3:23 ` David Vorick
2017-04-06 3:42 ` Peter Todd
2017-04-06 5:46 ` Thomas Daede
2017-04-06 6:24 ` Jonathan Toomim
2017-04-06 12:04 ` David Vorick
[not found] ` <CAMZUoK=oDAD9nhFAHkgncWtYxjBNh3qXbUffOH57QMnqjhmN6g@mail.gmail.com>
[not found] ` <CAMZUoKn8tr3LGbks0TnaCx9NTP6MZUzQ8PE6jDq1xiqpYyYwow@mail.gmail.com>
2017-04-06 13:55 ` Russell O'Connor
2017-04-06 16:49 ` Marco
2017-04-06 17:04 ` Alex Mizrahi
2017-04-06 17:13 ` Alex Mizrahi
2017-04-07 12:59 ` Jannes Faber
2017-04-07 13:28 ` Erik Aronesty
2017-04-06 17:31 ` Jared Lee Richardson
2017-04-06 17:26 ` Jared Lee Richardson
2017-04-06 15:36 ` Alex Mizrahi
2017-04-06 17:51 ` Jorge Timón
2017-04-06 7:24 ` bfd
2017-04-06 9:17 ` Luke Dashjr
2017-04-06 12:02 ` Luv Khemani
2017-04-06 12:11 ` Bryan Bishop
2017-04-06 17:43 ` Timo Hanke
2017-04-06 12:30 ` Luv Khemani
2017-04-06 15:15 ` Jorge Timón
2017-04-06 15:41 ` Daniel Robinson
2017-04-06 16:13 ` Andreas Schildbach
2017-04-06 21:38 ` Gregory Maxwell
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