Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1Y5omj-0001hw-Qa for bitcoin-development@lists.sourceforge.net; Tue, 30 Dec 2014 04:51:57 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.223.178 as permitted sender) client-ip=209.85.223.178; envelope-from=gmaxwell@gmail.com; helo=mail-ie0-f178.google.com; Received: from mail-ie0-f178.google.com ([209.85.223.178]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1Y5omi-0002VR-Os for bitcoin-development@lists.sourceforge.net; Tue, 30 Dec 2014 04:51:57 +0000 Received: by mail-ie0-f178.google.com with SMTP id vy18so11388894iec.37 for ; Mon, 29 Dec 2014 20:51:51 -0800 (PST) MIME-Version: 1.0 X-Received: by 10.107.30.204 with SMTP id e195mr52230737ioe.28.1419915111463; Mon, 29 Dec 2014 20:51:51 -0800 (PST) Received: by 10.107.16.30 with HTTP; Mon, 29 Dec 2014 20:51:51 -0800 (PST) In-Reply-To: <54A1A99E.1020604@certimix.com> References: <54A1A99E.1020604@certimix.com> Date: Tue, 30 Dec 2014 04:51:51 +0000 Message-ID: From: Gregory Maxwell To: Sergio Lerner Content-Type: text/plain; charset=UTF-8 X-Spam-Score: -1.6 (-) 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 (gmaxwell[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record -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: 1Y5omi-0002VR-Os Cc: bitcoin-development Subject: Re: [Bitcoin-development] BIP: Voluntary deposit bonds 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: Tue, 30 Dec 2014 04:51:57 -0000 On Mon, Dec 29, 2014 at 7:21 PM, Sergio Lerner wrote: > I propose to allow miners to voluntarily lock funds by letting miners > add additional inputs to the coinbase transaction. Currently the > coinbase transaction does not allow any real input to be added (only a > pseudo-input). > This is a hard-fork, and we could include it the next time a hardfork is > made. > The modifications to the code are minimal (no more than 12 lines > modified where IsCoinBase() is called), and they generally involve > removing code, not adding. If the motivation is purely enabling different rules in a soft-fork than I think nothing needs to be done. Instead of providing inputs to a coinbase: you provide an unusual anyone can spend transaction in the block which pays to fees; and simultaneously add a soft-forking rule that makes that anyone can spend rule no longer anyone can spend. To make that more concrete. E.g. You make your anyone can spend output "PUSH OP_NOP3". Now this anyone can pay transaction is really just a coinbase input. The construction is reasonably efficient, and also more flexible-- in that it could control the data under the hash in more flexible ways than available in the existing sighash flags. As an aside, I'm not sure that I agree with the claim that making coinbases have inputs is a simple modification... as we use one of the inputs already as the special coinbase field and at least that must be special cased.