Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1Um9gU-0005cG-Mm for bitcoin-development@lists.sourceforge.net; Mon, 10 Jun 2013 21:31:26 +0000 Received-SPF: pass (sog-mx-4.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.215.45 as permitted sender) client-ip=209.85.215.45; envelope-from=melvincarvalho@gmail.com; helo=mail-la0-f45.google.com; Received: from mail-la0-f45.google.com ([209.85.215.45]) by sog-mx-4.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1Um9gT-00010j-8r for bitcoin-development@lists.sourceforge.net; Mon, 10 Jun 2013 21:31:26 +0000 Received: by mail-la0-f45.google.com with SMTP id fr10so6235250lab.32 for ; Mon, 10 Jun 2013 14:31:18 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.112.189.101 with SMTP id gh5mr7336682lbc.73.1370899878441; Mon, 10 Jun 2013 14:31:18 -0700 (PDT) Received: by 10.112.2.8 with HTTP; Mon, 10 Jun 2013 14:31:18 -0700 (PDT) In-Reply-To: <20130610210913.GA17242@petertodd.org> References: <20130527111149.GB8955@tilt> <20130531165445.GA29104@petertodd.org> <20130531165758.GA29135@petertodd.org> <20130610210913.GA17242@petertodd.org> Date: Mon, 10 Jun 2013 23:31:18 +0200 Message-ID: From: Melvin Carvalho To: Peter Todd Content-Type: multipart/alternative; boundary=001a11c3738a46f9bc04ded3807e X-Spam-Score: -0.6 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -1.5 SPF_CHECK_PASS SPF reports sender host as permitted sender for sender-domain 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (melvincarvalho[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 1.0 HTML_MESSAGE BODY: HTML included in message -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature X-Headers-End: 1Um9gT-00010j-8r Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Decentralizing mining X-BeenThere: bitcoin-development@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 10 Jun 2013 21:31:26 -0000 --001a11c3738a46f9bc04ded3807e Content-Type: text/plain; charset=ISO-8859-1 On 10 June 2013 23:09, Peter Todd wrote: > So here's the parts that need to be done for step #1: > > > # Protocol Work > > Basic idea is the miner makes two connections, their pool, and a local > bitcoind. > > They always (usually?) work on the subset of transactions common to both > the pool's getblocktemplate and their local one. When they find a share > if it doesn't meet difficulty they just hand it to the pool. Currently > that is done by handing the whole block over, correct? I know the BIP > says otherwise, but we should optimize this to just hand over tx hashes > where possible. > > If the share does meet difficulty, hand it to both the pool and the > local bitcoind. Should hand it to the pool first though, because the > pool likely has the fastest block propagation, then hand it to local > bitcoind. An optimized version may want to have some record of measured > bandwidth - this applies Bitcoin in general too, although also has other > issues. > > > ## Reducing bandwidth > > How about for normal shares we just pass the block header, and have the > pool randomly pick a subset of transactions to audit? Any fraud cancels > the users shares. This will work best in conjunction with a UTXO proof > tree to prove fees, or by just picking whole shares randomly to audit. > > We'll need persistent share storage so if your connection disconnects > you can provide the pool with the full share later though. > > Incedentally, note how the miner can do the reverse: pick random block > headers and challenge the pool to prove that they correspond to a valid > block. With some modifications Stratum can support this approach. > > > ## Delibrate orphaning of slow to propagate blocks > > Block headers can be flooded-filled much faster than blocks themselves. > They are also small enough to fit into a UDP packet. Nodes should pass > headers around separately via UDP, optinally with some tiny number of > transactions. When we see a valid block header whose contents we do not > know about a miner should switch to mining empty or near empty blocks in > solo mode that would orphan the still propagating block. Doing this is > safe, we'll never build on an invalid block, economically rational while > the inflation subsidy is still high, and helps reduce (although not > eliminate!) the advantage a large miner with high-bandwidth connections > has over those who don't. > > Of course, the other option is to build a block extending the one you > don't know about, which is even more rational, but doing poses major > risks to Bitcoin... > > This functionality can be implemented later - it's not strictly part of > pooled-solo mode. > > > # Pool work > > So does eliopool already accept arbitrary shares like this and do the > correct accounting already? (IE adjust share amount based on fees?) What > happens when the pool doesn't get the share directly, but does see the > new block? > > + possible protocol extensions > > > # Miner work > > Basically we need code to merge the two block templates together to find > commonality. I guess you probably want to implement this in bfgminer > first, so add the code to libblkmaker first, then maybe python-blkmaker. > > We also want an automatic fallback to local solo mining if the pool > can't be contacted. > > + possible protocol extensions > Sounds very promising. Suspect it will need a fair amount of testing ... > > > -- > 'peter'[:-1]@petertodd.org > 000000000000005576673e616271f762a5d8779d5fe7796c6e43ed43df5aa189 > > > ------------------------------------------------------------------------------ > This SF.net email is sponsored by Windows: > > Build for Windows Store. > > http://p.sf.net/sfu/windows-dev2dev > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > > --001a11c3738a46f9bc04ded3807e Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable



On 10 June 2013 23:09, Peter Todd <pete@petertodd.org> wrote:
So here's the parts that need to be done= for step #1:


# Protocol Work

Basic idea is the miner makes two connections, their pool, and a local
bitcoind.

They always (usually?) work on the subset of transactions common to both the pool's getblocktemplate and their local one. When they find a share=
if it doesn't meet difficulty they just hand it to the pool. Currently<= br> that is done by handing the whole block over, correct? I know the BIP
says otherwise, but we should optimize this to just hand over tx hashes
where possible.

If the share does meet difficulty, hand it to both the pool and the
local bitcoind. Should hand it to the pool first though, because the
pool likely has the fastest block propagation, then hand it to local
bitcoind. An optimized version may want to have some record of measured
bandwidth - this applies Bitcoin in general too, although also has other issues.


## Reducing bandwidth

How about for normal shares we just pass the block header, and have the
pool randomly pick a subset of transactions to audit? Any fraud cancels
the users shares. This will work best in conjunction with a UTXO proof
tree to prove fees, or by just picking whole shares randomly to audit.

We'll need persistent share storage so if your connection disconnects you can provide the pool with the full share later though.

Incedentally, note how the miner can do the reverse: pick random block
headers and challenge the pool to prove that they correspond to a valid
block. With some modifications Stratum can support this approach.


## Delibrate orphaning of slow to propagate blocks

Block headers can be flooded-filled much faster than blocks themselves.
They are also small enough to fit into a UDP packet. Nodes should pass
headers around separately via UDP, optinally with some tiny number of
transactions. When we see a valid block header whose contents we do not
know about a miner should switch to mining empty or near empty blocks in solo mode that would orphan the still propagating block. Doing this is
safe, we'll never build on an invalid block, economically rational whil= e
the inflation subsidy is still high, and helps reduce (although not
eliminate!) the advantage a large miner with high-bandwidth connections
has over those who don't.

Of course, the other option is to build a block extending the one you
don't know about, which is even more rational, but doing poses major risks to Bitcoin...

This functionality can be implemented later - it's not strictly part of=
pooled-solo mode.


# Pool work

So does eliopool already accept arbitrary shares like this and do the
correct accounting already? (IE adjust share amount based on fees?) What happens when the pool doesn't get the share directly, but does see the<= br> new block?

+ possible protocol extensions


# Miner work

Basically we need code to merge the two block templates together to find commonality. I guess you probably want to implement this in bfgminer
first, so add the code to libblkmaker first, then maybe python-blkmaker.
We also want an automatic fallback to local solo mining if the pool
can't be contacted.

+ possible protocol extensions

Sounds v= ery promising.=A0 Suspect it will need a fair amount of testing ...
=A0


--
'peter'[:-1]@pet= ertodd.org
000000000000005576673e616271f762a5d8779d5fe7796c6e43ed43df5aa189

---------------------------------------------------------= ---------------------
This SF.net email is sponsored by Windows:

Build for Windows Store.

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_________________________________________= ______
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