public inbox for bitcoindev@googlegroups.com
 help / color / mirror / Atom feed
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.


  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=8760z4rbng.fsf@rustcorp.com.au \
    --to=rusty@rustcorp.com.au \
    --cc=bitcoin-dev@lists.linuxfoundation.org \
    --cc=gavinandresen@gmail.com \
    --cc=pieter.wuille@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox