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| author | Bob McElrath <bob_bitcoin@mcelrath.org> | 2015-12-19 19:30:45 +0000 |
|---|---|---|
| committer | bitcoindev <bitcoindev@gnusha.org> | 2015-12-19 19:30:47 +0000 |
| commit | fd51b0bdad0078ad6ac1f7b5afbafd9641f6ec1b (patch) | |
| tree | c1bd1b33e997f6610ff07618a4d330f3a1e214c1 | |
| parent | 79efc763dea869e69bd8c0448153ab683197e271 (diff) | |
| download | pi-bitcoindev-fd51b0bdad0078ad6ac1f7b5afbafd9641f6ec1b.tar.gz pi-bitcoindev-fd51b0bdad0078ad6ac1f7b5afbafd9641f6ec1b.zip | |
Re: [bitcoin-dev] We need to fix the block withholding attack
| -rw-r--r-- | bf/270d9f3b7389152def03936a9c066391f18e65 | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/bf/270d9f3b7389152def03936a9c066391f18e65 b/bf/270d9f3b7389152def03936a9c066391f18e65 new file mode 100644 index 000000000..3fe9efc5c --- /dev/null +++ b/bf/270d9f3b7389152def03936a9c066391f18e65 @@ -0,0 +1,95 @@ +Return-Path: <bob_bitcoin@mcelrath.org> +Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org + [172.17.192.35]) + by mail.linuxfoundation.org (Postfix) with ESMTPS id 63B63EC0 + for <bitcoin-dev@lists.linuxfoundation.org>; + Sat, 19 Dec 2015 19:30:47 +0000 (UTC) +X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 +Received: from mcelrath.org (moya.mcelrath.org [50.31.3.130]) + by smtp1.linuxfoundation.org (Postfix) with ESMTPS id B42BB125 + for <bitcoin-dev@lists.linuxfoundation.org>; + Sat, 19 Dec 2015 19:30:46 +0000 (UTC) +Received: from mcelrath.org (localhost [127.0.0.1]) + by mcelrath.org (8.14.3/8.14.3/Debian-9.4) with ESMTP id tBJJUjPX023656 + (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); + Sat, 19 Dec 2015 19:30:45 GMT +Received: (from mcelrath@localhost) + by mcelrath.org (8.14.3/8.14.3/Submit) id tBJJUjBt023655; + Sat, 19 Dec 2015 19:30:45 GMT +X-Authentication-Warning: mcelrath.org: mcelrath set sender to + bob_bitcoin@mcelrath.org using -f +Date: Sat, 19 Dec 2015 19:30:45 +0000 +From: Bob McElrath <bob_bitcoin@mcelrath.org> +To: Peter Todd <pete@petertodd.org> +Message-ID: <20151219193045.GP20063@mcelrath.org> +References: <20151219184240.GB12893@muck> +MIME-Version: 1.0 +Content-Type: text/plain; charset=us-ascii +Content-Disposition: inline +In-Reply-To: <20151219184240.GB12893@muck> +User-Agent: Mutt/1.5.20 (2009-06-14) +X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,T_RP_MATCHES_RCVD + autolearn=ham version=3.3.1 +X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on + smtp1.linux-foundation.org +Cc: bitcoin-dev@lists.linuxfoundation.org +Subject: Re: [bitcoin-dev] We need to fix the block withholding attack +X-BeenThere: bitcoin-dev@lists.linuxfoundation.org +X-Mailman-Version: 2.1.12 +Precedence: list +List-Id: Bitcoin Development Discussion <bitcoin-dev.lists.linuxfoundation.org> +List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/bitcoin-dev>, + <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=unsubscribe> +List-Archive: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/> +List-Post: <mailto:bitcoin-dev@lists.linuxfoundation.org> +List-Help: <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=help> +List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>, + <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=subscribe> +X-List-Received-Date: Sat, 19 Dec 2015 19:30:47 -0000 + +Peter Todd via bitcoin-dev [bitcoin-dev@lists.linuxfoundation.org] wrote: +> One of the issues raised by the pools present was block withholding +> attacks, which they said are a real issue for them. In particular, pools +> are receiving legitimate threats by bad actors threatening to use block +> withholding attacks against them. + +The only possible other bad actors are other miners. So who are the "bad actor" +miners? It's a short list of candidates. + +> P2Pool is often brought up as a replacement for pools, but it itself is still +> relatively vulnerable to block withholding, and in any case has many other +> vulnerabilities and technical issues that has prevented widespread adoption of +> P2Pool. + +I've been trying to understand this source of "vulnerabilities and technical +issues" with p2pool and have received a lot of contradictory information. Can +someone in the know summarize what the problems with p2pool are? + +The economic situation where miners can be deprived of profit due to the lack of +synchronicity in block updates is a physics problem due to the size of the Earth +and will never be removed. This is a design flaw in Bitcoin. Therefore a +different, more comprehensive solution is called for. + +My solution to this is somewhat longer term and needs more simulation but +fundamentally removes the source of contention and fixes the design flaw, while +remaining as close "in spirit" to bitcoin as possible: + https://scalingbitcoin.org/hongkong2015/presentations/DAY2/2_breaking_the_chain_1_mcelrath.pdf +Not only does block withholding simply not work to deny other miners income due +to the absence of orphans, but I explicitly added a dis-incentive against +withholding blocks in terms of the "cohort difficulty". Other graph-theoretic +quantities are in general possible in the reward function to better align the +incentives of miners with the correct operation of the system. Also by lowering +the target difficulty and increasing the block (bead) rate, one lowers the +variance of miner income. + +Part of the reason I ask is that there has been some interest in testing my +ideas in p2pool itself (or a new similar share pool), but I'm failing to +understand the source of all the complaints about p2pool. + +-- +Cheers, Bob McElrath + +"For every complex problem, there is a solution that is simple, neat, and wrong." + -- H. L. Mencken + + |