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 1UjePX-0007ZA-Ad for bitcoin-development@lists.sourceforge.net; Mon, 03 Jun 2013 23:43:35 +0000 Received-SPF: pass (sog-mx-4.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.217.172 as permitted sender) client-ip=209.85.217.172; envelope-from=melvincarvalho@gmail.com; helo=mail-lb0-f172.google.com; Received: from mail-lb0-f172.google.com ([209.85.217.172]) by sog-mx-4.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1UjePV-0000Pd-V6 for bitcoin-development@lists.sourceforge.net; Mon, 03 Jun 2013 23:43:35 +0000 Received: by mail-lb0-f172.google.com with SMTP id p10so29288lbi.31 for ; Mon, 03 Jun 2013 16:43:27 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.112.202.35 with SMTP id kf3mr11866530lbc.122.1370303007219; Mon, 03 Jun 2013 16:43:27 -0700 (PDT) Received: by 10.112.20.231 with HTTP; Mon, 3 Jun 2013 16:43:27 -0700 (PDT) In-Reply-To: <20130601193036.GA13873@savin> References: <20130601193036.GA13873@savin> Date: Tue, 4 Jun 2013 01:43:27 +0200 Message-ID: From: Melvin Carvalho To: Peter Todd Content-Type: multipart/alternative; boundary=001a11c377a2fae4a804de4887cf 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: 1UjePV-0000Pd-V6 Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Proposal: soft-fork to make anyone-can-spend outputs unspendable for 100 blocks 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, 03 Jun 2013 23:43:35 -0000 --001a11c377a2fae4a804de4887cf Content-Type: text/plain; charset=ISO-8859-1 On 1 June 2013 21:30, Peter Todd wrote: > Currently the most compact way (proof-size) to sacrifice Bitcoins that > does not involve making them unspendable is to create a anyone-can-spend > output as the last txout in the coinbase of a block: > > scriptPubKey: OP_TRUE > > The proof is then the SHA256 midstate, the txout, and the merkle path to > the block header. However this mechanism needs miner support, and it is > not possible to pay for such a sacrifice securely, or create an > assurance contract to create one. > Sorry if this is a stupid question, but why would someone want to sacrifice their bitcoins? > > A anyone-can-spend in a regular txout is another option, but there is no > way to prevent a miner from including a transaction spending that txout > in the same block. Once that happens, there is no way to prove the miner > didn't create both, thus invalidating the sacrifice. The announce-commit > protocol solves that problem, but at the cost of a much larger proof, > especially if multiple parties want to get together to pay the cost of > the sacrifice. (the proof must include the entire tx used to make the > sacrifice) > > However if we add a rule where txouts ending in OP_TRUE are unspendable > for 100 blocks, similar to coinbases, we fix these problems. The rule > can be done as a soft-fork with 95% support in the same way the > blockheight rule was implemented. Along with that change > anyone-can-spend outputs should be make IsStandard() so they will be > relayed. > > The alternative is sacrifices to unspendable outputs, which is very > undesirable compared to sending the money to miners to further > strengthen the security of the network. > > We should always make it easy for people to write code that does what is > best for Bitcoin. > > -- > 'peter'[:-1]@petertodd.org > 00000000000000ce3427502ee6a254fed27e1cd21a656a335cd2ada79b7b5293 > > > ------------------------------------------------------------------------------ > Get 100% visibility into Java/.NET code with AppDynamics Lite > It's a free troubleshooting tool designed for production > Get down to code-level detail for bottlenecks, with <2% overhead. > Download for free and get started troubleshooting in minutes. > http://p.sf.net/sfu/appdyn_d2d_ap2 > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > > --001a11c377a2fae4a804de4887cf Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable



On 1 June 2013 21:30, Peter Todd <pete@petertodd.org> wrote:
Currently the most compact way (proof-size) = to sacrifice Bitcoins that
does not involve making them unspendable is to create a anyone-can-spend output as the last txout in the coinbase of a block:

scriptPubKey: <data> OP_TRUE

The proof is then the SHA256 midstate, the txout, and the merkle path to the block header. However this mechanism needs miner support, and it is
not possible to pay for such a sacrifice securely, or create an
assurance contract to create one.

Sorry= if this is a stupid question, but why would someone want to sacrifice thei= r bitcoins?
=A0

A anyone-can-spend in a regular txout is another option, but there is no way to prevent a miner from including a transaction spending that txout
in the same block. Once that happens, there is no way to prove the miner didn't create both, thus invalidating the sacrifice. The announce-commi= t
protocol solves that problem, but at the cost of a much larger proof,
especially if multiple parties want to get together to pay the cost of
the sacrifice. (the proof must include the entire tx used to make the
sacrifice)

However if we add a rule where txouts ending in OP_TRUE are unspendable
for 100 blocks, similar to coinbases, we fix these problems. The rule
can be done as a soft-fork with 95% support in the same way the
blockheight rule was implemented. Along with that change
anyone-can-spend outputs should be make IsStandard() so they will be
relayed.

The alternative is sacrifices to unspendable outputs, which is very
undesirable compared to sending the money to miners to further
strengthen the security of the network.

We should always make it easy for people to write code that does what is best for Bitcoin.

--
'peter'[:-1]@pet= ertodd.org
00000000000000ce3427502ee6a254fed27e1cd21a656a335cd2ada79b7b5293

---------------------------------------------------------= ---------------------
Get 100% visibility into Java/.NET code with AppDynamics Lite
It's a free troubleshooting tool designed for production
Get down to code-level detail for bottlenecks, with <2% overhead.
Download for free and get started troubleshooting in minutes.
http://p.s= f.net/sfu/appdyn_d2d_ap2
___________________________________________= ____
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Bitcoin-develo= pment@lists.sourceforge.net
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