Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-1.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1WNlnb-0002HK-Kl for bitcoin-development@lists.sourceforge.net; Wed, 12 Mar 2014 16:14:31 +0000 Received-SPF: pass (sog-mx-4.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.219.48 as permitted sender) client-ip=209.85.219.48; envelope-from=mh.in.england@gmail.com; helo=mail-oa0-f48.google.com; Received: from mail-oa0-f48.google.com ([209.85.219.48]) by sog-mx-4.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1WNlna-0004Wk-Sp for bitcoin-development@lists.sourceforge.net; Wed, 12 Mar 2014 16:14:31 +0000 Received: by mail-oa0-f48.google.com with SMTP id m1so10248531oag.7 for ; Wed, 12 Mar 2014 09:14:25 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.60.173.99 with SMTP id bj3mr1624471oec.55.1394640865618; Wed, 12 Mar 2014 09:14:25 -0700 (PDT) Sender: mh.in.england@gmail.com Received: by 10.76.71.231 with HTTP; Wed, 12 Mar 2014 09:14:25 -0700 (PDT) In-Reply-To: References: <531DFDF8.80008@gmail.com> <531E52FE.5090107@jerviss.org> <531E5454.1030601@gmail.com> <4fca6b510dd57d2f92affeb988d2ee5d.squirrel@fulvetta.riseup.net> <531FAA55.2020108@xeno-genesis.com> <531FC808.7060709@gmail.com> <9A6499BC-E546-45CC-A7EF-5182FC86052D@gmail.com> <53202D51.8010008@plan99.net> Date: Wed, 12 Mar 2014 17:14:25 +0100 X-Google-Sender-Auth: MuatrLgXIrJNsFOfV430gYkA604 Message-ID: From: Mike Hearn To: Drak Content-Type: multipart/alternative; boundary=047d7ba9818c6275a604f46b2191 X-Spam-Score: -0.5 (/) 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 (mh.in.england[at]gmail.com) -0.0 SPF_PASS SPF: sender matches SPF record 1.0 HTML_MESSAGE BODY: HTML included in message 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: 1WNlna-0004Wk-Sp Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Multisign payment protocol? 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: Wed, 12 Mar 2014 16:14:31 -0000 --047d7ba9818c6275a604f46b2191 Content-Type: text/plain; charset=UTF-8 > > Can this be calculated in advance knowing the initial transaction size and > the number of signatures required? > Sure of course. You assume each signature to be placed in the tx is 73 bytes. Not very hard, but if the tx you get back from the API doesn't contain such a 73-byte sentinel value then it's harder to be sure that this part was done correctly. --047d7ba9818c6275a604f46b2191 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Can this be= calculated in advance knowing the initial transaction size and the number = of signatures required?

Sure of course. You assume each signature to be placed = in the tx is 73 bytes. Not very hard, but if the tx you get back from the A= PI doesn't contain such a 73-byte sentinel value then it's harder t= o be sure that this part was done correctly.=C2=A0
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