From: Rusty Russell <rusty@rustcorp.com.au>
To: Pieter Wuille <pieter.wuille@gmail.com>,
Gavin Andresen <gavinandresen@gmail.com>
Cc: Bitcoin Dev <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] Time to worry about 80-bit collision attacks or not?
Date: Fri, 08 Jan 2016 14:00:11 +1030 [thread overview]
Message-ID: <8760z4rbng.fsf@rustcorp.com.au> (raw)
In-Reply-To: <CAPg+sBhH0MODjjp8Avx+Fy_UGqzMjUq_jn3vT3oH=u3711tsSA@mail.gmail.com>
Pieter Wuille via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org>
writes:
> Yes, this is what I worry about. We're constructing a 2-of-2 multisig
> escrow in a contract. I reveal my public key A, you do a 80-bit search for
> B and C such that H(A and B) = H(B and C). You tell me your keys B, and I
> happily send to H(A and B), which you steal with H(B and C).
FWIW, this attack would effect the current lightning-network "deployable
lightning" design at channel establishment; we reveal our pubkey in the
opening packet (which is used to redeem a P2SH using normal 2of2).
At least you need to grind before replying (which will presumably time
out), rather than being able to do it once the channel is open.
We could pre-commit by exchanging hashes of pubkeys first, but contracts
on bitcoin are hard enough to get right that I'm reluctant to add more
hoops.
Cheers,
Rusty.
next prev parent reply other threads:[~2016-01-08 3:30 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-07 19:02 [bitcoin-dev] Time to worry about 80-bit collision attacks or not? Gavin Andresen
2016-01-07 19:13 ` Matt Corallo
2016-01-07 19:19 ` Adam Back
2016-01-07 20:56 ` Dave Scotese
2016-01-07 21:06 ` Gavin Andresen
2016-01-07 22:56 ` Ethan Heilman
2016-01-07 23:39 ` Gavin Andresen
2016-01-08 1:26 ` Matt Corallo
2016-01-08 1:54 ` Gavin Andresen
2016-01-08 17:38 ` Pieter Wuille
2016-01-08 18:41 ` Peter Todd
2016-01-07 20:40 ` Ethan Heilman
2016-01-07 23:52 ` Pieter Wuille
2016-01-08 1:00 ` Gavin Andresen
2016-01-08 1:27 ` Watson Ladd
2016-01-08 3:30 ` Rusty Russell [this message]
2016-01-08 3:41 ` Matt Corallo
2016-01-08 12:02 ` Rusty Russell
2016-01-08 12:38 ` Gavin Andresen
2016-01-08 14:34 ` Watson Ladd
2016-01-08 15:26 ` Adam Back
2016-01-08 15:33 ` Anthony Towns
2016-01-08 15:46 ` Gavin Andresen
2016-01-08 15:50 ` Gavin Andresen
2016-01-08 15:59 ` Gavin Andresen
2016-01-11 20:32 ` Jorge Timón
2016-01-08 16:06 ` Gavin Andresen
2016-01-11 3:57 ` Rusty Russell
2016-01-11 6:57 ` Peter Todd
2016-01-11 23:57 ` Tier Nolan
2016-01-12 0:00 ` Tier Nolan
2016-01-12 12:08 ` Gavin Andresen
2016-01-12 23:22 ` Zooko Wilcox-O'Hearn
2016-01-08 18:52 ` Peter Todd
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