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From: Cameron Garnham <da2ce7@gmail.com>
In-Reply-To: <CAFmyj8zNkPj3my3CLzkXdpJ1xkD0GQk8ODg09qYnnj_ONGUtsQ@mail.gmail.com>
Date: Fri, 26 May 2017 11:02:27 +0300
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References: <D0299438-E848-4696-B323-8D0E810AE491@gmail.com>
	<CAFmyj8zNkPj3my3CLzkXdpJ1xkD0GQk8ODg09qYnnj_ONGUtsQ@mail.gmail.com>
To: "Andreas M. Antonopoulos" <andreas@antonopoulos.com>
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Emergency Deployment of SegWit as a partial
 mitigation of CVE-2017-9230
Precedence: list

Thank you for your reply Andreas,

I can assure you that I have many motivations for activating SegWit.

Before studding ASICBOOST I wanted to activate SegWit as it is a =
wonderful upgrade for Bitcoin. It seems to me that virtually the entire =
Bitcoin Ecosystem agrees with me.  Except for around 67% of the mining =
hash-rate who very conspicuously refuse to signal for it=E2=80=99s =
activation.=20

So, I started searching for the motivations of such a large amount of =
the mining hash-rate holding a position that isn=E2=80=99t at-all =
represented in the wider Bitcoin Community. My study of ASICBOOST lead =
to a =E2=80=98bingo=E2=80=99 moment:  If one assumes that the 67% of the =
hash rate that refuse to signal for SegWit are using ASICBOOST. The =
entire picture of this political stalemate became much more =
understandable.

This only strengthened my resolve to activate SegWit: not only is SegWit =
great, it partially mitigates a very serious security vulnerability.

This is why I call into question why you would suggest:

=E2=80=9CThis proposal is unnecessarily conflating two contentious =
issues and will attract criticism of self serving motivation.=E2=80=9D

1. I am not conflating the issues.  I would argue that very fact that =
SegWit has not been activated yet is directly because of CVE-2017-9230.
2. I have no reason to believe that SegWit is contentious, except for =
the attackers who it would frustrate.
3. I have no negative responses to my endeavours to get ASICBOOST as =
regarded as a legitimate security vulnerability.  This would suggest =
that it is not contentious in the wider technical community.

If SegWit is NOT contentious within the technical community and it is =
NOT contentious to regard CVE-2017-9230 as a credible security =
vulnerability. Then using it as partial security fix for a security =
vulnerability SHOULD NOT be contentious.

If you believe that SegWit is contentious within the technical =
community.  Or you believe CVE-2017-9230 should not be regarded as a =
credible security vulnerability. Then I would logically agree with you =
that we should separate the issues so that we may gain consensus. =
However, I just don=E2=80=99t see this as the case.

Cameron.


> On 26 May 2017, at 09:52 , Andreas M. Antonopoulos =
<andreas@antonopoulos.com> wrote:
>=20
> I rarely post here, out of respect to the mailing list. But since my =
name was mentioned...=20
>=20
> I much prefer Gregory Maxwell's proposal to defuse covert ASICBOOST =
(only) with a segwit-like commitment to the coinbase which does not =
obligate miners to signal Segwit or implement Segwit, thus disarming any =
suspicion that the issue is being exploited only to activate Segwit.
>=20
> This proposal is unnecessarily conflating two contentious issues and =
will attract criticism of self serving motivation.
>=20
> Politicising CVE  is damaging to the long term bitcoin development and =
to its security. Not claiming that is the intent here, but the damage is =
done by the mere appearance of motive.=20
>=20
>=20
>=20
> On May 26, 2017 16:30, "Cameron Garnham via bitcoin-dev" =
<bitcoin-dev@lists.linuxfoundation.org> wrote:
> Hello Bitcoin-Dev,
>=20
> CVE-2017-9230 (1) (2), or commonly known as =E2=80=98ASICBOOST=E2=80=99 =
is a severe (3) (4) and actively exploited (5) security vulnerability.
>=20
> To learn more about this vulnerability please read Jeremy Rubin=E2=80=99=
s detailed report:
> http://www.mit.edu/~jlrubin//public/pdfs/Asicboost.pdf
>=20
> Andreas Antonopoulos has an excellent presentation on why asicboost is =
dangerous:
> https://www.youtube.com/watch?v=3Dt6jJDD2Aj8k
>=20
> In decisions on the #bitcoin-core-dev IRC channel; It was proposed, =
without negative feedback, that SegWit be used as a partial-mitigation =
of CVE-2017-9230.
>=20
> SegWit partially mitigates asicboost with the common reasonable =
assumption that any block that doesn=E2=80=99t include a witness commit =
in it's coinbase transaction was mined using covert asicboost.  Making =
the use of covert asicboost far more conspicuous.
>=20
> It was also proposed that this partial mitigation should be quickly =
strengthened via another soft-fork that makes the inclusion of witness =
commits mandatory, without negative feedback.
>=20
> The security trade-offs of deploying a partial-mitigation to =
CVE-2017-9230 quickly vs more slowly but more conservatively is under =
intense debate.  The author of this post has a strong preference to the =
swiftest viable option.
>=20
> Cameron.
>=20
>=20
> (1) CVE Entry:
> https://cve.mitre.org/cgi-bin/cvename.cgi?name=3D+CVE-2017-9230
>=20
> (2) Announcement of CVE to Mailing List:
> =
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-May/014416.ht=
ml
>=20
> (3) Discussion of the perverse incentives created by 'ASICBOOST' by =
Ryan Grant:
>  =
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-May/014352.ht=
ml
>=20
> (4) Discussion of ASICBOOST's non-independent PoW calculation by Tier =
Nolan:
>  =
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-May/014351.ht=
ml
>=20
> (5) Evidence of Active Exploit by Gregory Maxwell:
> =
https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2017-April/013996.=
html
>=20
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