From: Steve Davis <steven.charles.davis@gmail.com>
Message-Id: <C3BDCE95-6DA6-44E4-AFB8-14F9B84ABC02@gmail.com>
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Date: Sun, 26 Feb 2017 01:16:37 -0600
In-Reply-To: <CAPg+sBgndv+Q-MGhz6Th9A3xhtqouz6D9AENqRusnCz_m+2O2g@mail.gmail.com>
To: Pieter Wuille <pieter.wuille@gmail.com>
References: <8F096BE1-D305-43D4-AF10-2CC48837B14F@gmail.com>
	<20170225010122.GA10233@savin.petertodd.org>
	<208F93FE-B7C8-46BE-8E00-52DBD0F43415@gmail.com>
	<CAN6UTayzQRowtWhLKr8LyFuXjw3m+GjQGtHfkDj-Xu41Hym32w@mail.gmail.com>
	<CAEM=y+WkgSkc07ZsU6APAkcu37zVZ7dwSc=jAg1nho31S5ZyxQ@mail.gmail.com>
	<20170225191201.GA15472@savin.petertodd.org>
	<CAMZUoK=sq_sRoXuySca-VAGwA3AzeoZ5iNFSnKULbj+NtPjHFA@mail.gmail.com>
	<20170225210406.GA16196@savin.petertodd.org>
	<CAGLBAhdCb+QLWRm4FWkPvaM2sU24HuafdgNiS=wgnPTGzrW05w@mail.gmail.com>
	<4FE38F6A-0560-4989-9C53-7F8C94EA4C76@gmail.com>
	<20170225214018.GA16524@savin.petertodd.org>
	<D36DB0BD-C805-4346-B425-77D5B29582E5@gmail.com>
	<CAPg+sBhZ1UqOLqz_PVjjrE8Cbte_Y160Gq7P7EWf6cRKjMcDEQ@mail.gmail.com>
	<4F6C2972-A320-429A-BD13-623B01F390A3@gmail.com>
	<CAPg+sBgndv+Q-MGhz6Th9A3xhtqouz6D9AENqRusnCz_m+2O2g@mail.gmail.com>
Cc: Bitcoin Dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] SHA1 collisions make Git vulnerable to attakcs by
 third-parties, not just repo maintainers
Precedence: list


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> On Feb 26, 2017, at 12:36 AM, Pieter Wuille <pieter.wuille@gmail.com> =
wrote:
>=20
> The 80-bit collision attack only applies to jointly constructed =
addresses like multisig P2SH, not single-key ones.

That=E2=80=99s the part I=E2=80=99m less convinced about, and why I =
asked the original question re SHA1 vs RIPEMD.=20

I=E2=80=99m checking my own numbers (and as you=E2=80=99ll appreciate =
it=E2=80=99s a powers of ten thing), but I do see a vector. Which would =
mean that if RIPEMD were weakened in any way, single-key transactions =
could suddenly become badly exposed.


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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dutf-8"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" =
class=3D""><br class=3D""><div><blockquote type=3D"cite" class=3D""><div =
class=3D"">On Feb 26, 2017, at 12:36 AM, Pieter Wuille &lt;<a =
href=3D"mailto:pieter.wuille@gmail.com" =
class=3D"">pieter.wuille@gmail.com</a>&gt; wrote:</div><br =
class=3D"Apple-interchange-newline"><div class=3D""><span =
style=3D"font-family: Helvetica; font-size: 12px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
orphans: auto; text-align: start; text-indent: 0px; text-transform: =
none; white-space: normal; widows: auto; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; float: none; display: inline =
!important;" class=3D"">The 80-bit collision attack only applies to =
jointly constructed addresses like multisig P2SH, not single-key =
ones.</span></div></blockquote></div><br class=3D""><div =
class=3D"">That=E2=80=99s the part I=E2=80=99m less convinced about, and =
why I asked the original question re SHA1 vs RIPEMD.&nbsp;</div><div =
class=3D""><br class=3D""></div><div class=3D"">I=E2=80=99m checking my =
own numbers (and as you=E2=80=99ll appreciate it=E2=80=99s a powers of =
ten thing), but I do see a vector. Which would mean that if RIPEMD were =
weakened in any way, single-key transactions could suddenly become badly =
exposed.</div><div class=3D""><br class=3D""></div></body></html>=

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