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From: Alice Wonder <alice@librelamp.com>
To: bitcoin-dev@lists.linuxfoundation.org
Subject: Re: [bitcoin-dev] SHA1 collisions make Git vulnerable to attakcs by third-parties, not just repo maintainers
Date: Sat, 25 Feb 2017 10:19:11 -0800	[thread overview]
Message-ID: <f309ea73-053d-c3e9-134e-4561e89715f1@librelamp.com> (raw)
In-Reply-To: <CAEM=y+WkgSkc07ZsU6APAkcu37zVZ7dwSc=jAg1nho31S5ZyxQ@mail.gmail.com>

On 02/25/2017 08:10 AM, Ethan Heilman via bitcoin-dev wrote:
>>SHA1 is insecure because the SHA1 algorithm is insecure, not because
> 160bits isn't enough.
>
> I would argue that 160-bits isn't enough for collision resistance.
> Assuming RIPEMD-160(SHA-256(msg)) has no flaws (i.e. is a random
> oracle), collisions can be generated in 2^80 queries (actually detecting
> these collisions requires some time-memory additional trade-offs). The
> Bitcoin network at the current hash rate performs roughly SHA-256 ~2^78
> queries a day or 2^80 queries every four days.

You have to not only produce a ripemd160 collision, you have to produce 
a collision that is also a valid sha-256 hash - and that's much much 
much more difficult.



  parent reply	other threads:[~2017-02-25 18:28 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <mailman.22137.1487974823.31141.bitcoin-dev@lists.linuxfoundation.org>
2017-02-24 23:49 ` [bitcoin-dev] SHA1 collisions make Git vulnerable to attakcs by third-parties, not just repo maintainers Steve Davis
2017-02-25  1:01   ` Peter Todd
2017-02-25 12:04     ` Steve Davis
2017-02-25 14:50       ` Leandro Coutinho
2017-02-25 16:10         ` Ethan Heilman
2017-02-25 17:45           ` Shin'ichiro Matsuo
2017-02-27  9:15             ` Henning Kopp
2017-02-25 18:19           ` Alice Wonder [this message]
2017-02-25 18:36             ` Ethan Heilman
2017-02-25 19:12           ` Peter Todd
2017-02-25 20:42             ` Watson Ladd
2017-02-25 20:57               ` Peter Todd
2017-02-25 20:53             ` Russell O'Connor
2017-02-25 21:04               ` Peter Todd
2017-02-25 21:21                 ` Dave Scotese
2017-02-25 21:34                   ` Steve Davis
2017-02-25 21:40                     ` Peter Todd
2017-02-25 21:54                       ` Steve Davis
2017-02-25 22:14                         ` Pieter Wuille
2017-02-25 22:34                           ` Ethan Heilman
2017-02-26  6:26                           ` Steve Davis
2017-02-26  6:36                             ` Pieter Wuille
2017-02-26  7:16                               ` Steve Davis
     [not found]                                 ` <CAPg+sBirowtHqUT5GUJf9hmDEACKVX19HAon-rrz7GmO8OBsNg@mail.gmail.com>
2017-02-26 16:53                                   ` Steve Davis
2017-02-25 23:09                       ` Leandro Coutinho
2017-02-23 18:14 Peter Todd
2017-02-23 21:28 ` Peter Todd
2017-02-23 23:57   ` Aymeric Vitte
2017-02-24 10:04     ` Tim Ruffing
2017-02-24 15:18       ` Aymeric Vitte
2017-02-24 16:30         ` Tim Ruffing
2017-02-24 17:29           ` Aymeric Vitte

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