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From: Alessandro Parisi <startithub@gmail.com>
To: Patrick <patrick@intersango.com>
Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] BIP proposal - patch to raise selfish mining threshold.
Date: Tue, 5 Nov 2013 19:18:22 +0100	[thread overview]
Message-ID: <CADre0dkw+Lhh9HodgPz0u4MgxkpO+KJhCoGfDbOQZM3TExab+w@mail.gmail.com> (raw)
In-Reply-To: <52792CF2.10709@intersango.com>

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Patrick, could you please explain us why the solution proposed by Ittay
would drop the actual honest miners ratio, becoming so backfire? Thanks a
lot


2013/11/5 Patrick <patrick@intersango.com>

>  The ratio of honest miners that mine the first block they see is > 0.5
>
> Your proposed solution would reduce that ratio to 0.5
>
> In other words your proposed change would make the attack you describe
> easier not harder.
>
>
> On 11/05/2013 09:26 AM, Ittay wrote:
>
> That sounds like selfish mining, and the magic number is 25%. That's the
> minimal pool size.
> Today the threshold is 0% with good connectivity.
>
>  If I misunderstood your point, please elaborate.
>
>  Ittay
>
>
>
> On Tue, Nov 5, 2013 at 12:05 PM, Peter Todd <pete@petertodd.org> wrote:
>
>> On Tue, Nov 05, 2013 at 11:56:53AM -0500, Ittay wrote:
>> > Hello,
>> >
>> > Please see below our BIP for raising the selfish mining threshold.
>> > Looking forward to your comments.
>>
>>  <snip>
>>
>> > 2. No new vulnerabilities introduced:
>> > Currently the choice among equal-length chains is done arbitrarily,
>> > depending on network topology. This arbitrariness is a source of
>> > vulnerability. We replace it with explicit randomness, which is at the
>> > control of the protocol. The change does not introduce executions that
>> were
>> > not possible with the old protocol.
>>
>>  Credit goes to Gregory Maxwell for pointing this out, but the random
>> choice solution does in fact introduce a vulnerability in that it
>> creates incentives for pools over a certain size to withhold blocks
>> rather than immediately broadcasting all blocks found.
>>
>> The problem is that when the pool eventually choses to reveal the block
>> they mined, 50% of the hashing power switches, thus splitting the
>> network. Like the original attack this can be to their benefit. For
>> pools over a certain size this strategy is profitable even without
>> investing in a low-latency network; Maxwell or someone else can chime in
>> with the details for deriving that threshold.
>>
>> I won't get a chance to for a few hours, but someone should do the
>> analysis on a deterministic switching scheme.
>>
>> --
>> 'peter'[:-1]@petertodd.org
>> 0000000000000005e25ca9b9fe62bdd6e8a2b4527ad61753dd2113c268bec707
>>
>
>
>
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  reply	other threads:[~2013-11-05 18:18 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-05 16:56 [Bitcoin-development] BIP proposal - patch to raise selfish mining threshold Ittay
2013-11-05 17:05 ` Peter Todd
2013-11-05 17:14   ` Peter Todd
2013-11-05 17:43     ` Ittay
2013-11-05 17:54       ` Mike Hearn
2013-11-05 18:07         ` Alessandro Parisi
2013-11-05 18:37           ` Jeff Garzik
2013-11-05 18:55             ` Alessandro Parisi
2013-11-05 18:58               ` Jeff Garzik
2013-11-05 19:33                 ` Jameson Lopp
2013-11-05 19:56       ` Peter Todd
2013-11-05 17:26   ` Ittay
2013-11-05 17:37     ` Patrick
2013-11-05 18:18       ` Alessandro Parisi [this message]
2013-11-05 18:57     ` Jeremy Spilman
2013-11-05 22:49       ` Ittay
2013-11-07 20:05 ` [Bitcoin-development] comments on selfish-mining model (Re: BIP proposal - patch to raise selfish mining threshold.) Adam Back

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