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From: Mike Hearn <mike@plan99.net>
To: Peter Todd <pete@petertodd.org>
Cc: Ittay Eyal <ittay.eyal@cornell.edu>,
	Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Auto-generated miner backbone
Date: Mon, 4 Nov 2013 16:27:58 +0100	[thread overview]
Message-ID: <CANEZrP0pUvyP62NKu2hdzFYxaMdD7iPPmkL699-gZksZa=HHzg@mail.gmail.com> (raw)
In-Reply-To: <20131104142621.GA2190@petertodd.org>

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On Mon, Nov 4, 2013 at 3:26 PM, Peter Todd <pete@petertodd.org> wrote:

> The attacker now only needs to connect to every identified miner
> with especially fast nodes. With judicious use of DoS attacks and low
> latency .....
>

So you're back to a complicated sybil attack. I don't follow your thought
process here - I didn't say anything about numerical advantage. The attack
outlined in the paper *requires* you to be able to race the rest of the
network and win some non-trivial fraction of the time. If you can't do that
then all it means is that when you try to release a private block to
compete with the other found block, you're quite likely to lose and you
sacrifice the block rewards by doing so.


> The correct, and rational, approach for a miner is to always mine to
> extend the block that the majority of hashing power is trying to extend.
>

There's no stable way to know that. The whole purpose of the block chain to
establish the majority. I think your near-miss headers solution is
circular/unstable for that reason, it's essentially a recursive solution.


> Mining strategy is now to mine to extend the first block you see, on the
> assumption that the earlier one probably propagated to a large portion
> of the total hashing power. But as you receive "near-blocks" that are
> under the PoW target, use them to estimate the hashing power on each
> fork, and if it looks like you are not on the majority side, switch.
>

But you can't reliably estimate that. You can't even reliably estimate the
speed of the overall network especially not on a short term basis like a
block interval.

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  parent reply	other threads:[~2013-11-04 15:28 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-04 11:26 [Bitcoin-development] Auto-generated miner backbone Mike Hearn
2013-11-04 11:53 ` Peter Todd
2013-11-04 12:00   ` Mike Hearn
2013-11-04 18:16     ` [Bitcoin-development] Committing to extra block data/a better merge-mine standard Peter Todd
2013-11-04 18:32       ` Peter Todd
2013-11-04 19:11       ` Mark Friedenbach
2013-11-15 22:06         ` Peter Todd
2013-11-04 19:38       ` Mike Hearn
2013-11-04 19:53         ` Mark Friedenbach
2013-11-04 20:10           ` Mike Hearn
2013-11-04 11:58 ` [Bitcoin-development] Auto-generated miner backbone Michael Gronager
2013-11-04 12:03   ` Mike Hearn
2013-11-04 12:20     ` Peter Todd
2013-11-04 12:40     ` Michael Gronager
2013-11-04 15:58   ` Gregory Maxwell
2013-11-04 14:26 ` Peter Todd
2013-11-04 14:34   ` Pieter Wuille
2013-11-04 14:46     ` Peter Todd
     [not found]   ` <CABT1wWm1NzKSS9H=Qh3Z6pFmNHbOFKC12WaE=b3kE0mNsRgfmw@mail.gmail.com>
2013-11-04 15:04     ` Peter Todd
     [not found]       ` <CABT1wWmONUeOWRg-=FKr88bgBQf0un4bvjYW2h8d-10ys-VKtA@mail.gmail.com>
2013-11-04 15:46         ` Peter Todd
     [not found]           ` <CABT1wWmM466jWWdWAo5GmzP58xJFT70Vcr74ta+2QF2fWT+1SA@mail.gmail.com>
2013-11-04 16:07             ` Peter Todd
     [not found]               ` <CABT1wWm5BDZf7U40pOqZvTqdOKeTWUTekjUNckq5McMV=LDu_g@mail.gmail.com>
2013-11-04 16:51                 ` Peter Todd
     [not found]         ` <CABT1wWmwb17b4ACHMmDKqd94tUSKsvwAPx344mZ0VS+47myeWg@mail.gmail.com>
2013-11-04 21:04           ` Peter Todd
2013-11-04 21:45             ` Alan Reiner
2013-11-04 22:03               ` Peter Todd
2013-11-04 15:27   ` Mike Hearn [this message]
2013-11-04 17:36     ` Peter Todd
2013-11-04 15:51 ` Gregory Maxwell
2013-11-05  4:14 Gustaw Wieczorek
2013-11-05  4:39 ` Peter Todd
2013-11-05  6:37   ` Gregory Maxwell

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