From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id A5169B8A for ; Fri, 22 Sep 2017 21:39:51 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-pf0-f173.google.com (mail-pf0-f173.google.com [209.85.192.173]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 2CD22443 for ; Fri, 22 Sep 2017 21:39:51 +0000 (UTC) Received: by mail-pf0-f173.google.com with SMTP id r71so1135491pfe.12 for ; Fri, 22 Sep 2017 14:39:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=friedenbach-org.20150623.gappssmtp.com; s=20150623; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=MGH/KEfo/NyZuIxXGMn5Co300AjgYW567euZkx3T6tY=; b=VTRy6WfD4FRrJRQGemkF4iwYSaHpqUBrKjv+0DQa4W7KnSv32b2j9ATgjoQzoSckCN YyKEP51XhSR7S3E/NClsUs2gdsMlcg+SvS0OsRMepIAI8OUjTkpFTjTP08AVoMEY3zCO 8Ppi9RUwqRjNwqWYKO2xm8R4Igp69YMg8aM4Ne8PIx3LGMUFdSsP58m1zVe1Frxmb1+M grKcOyfRwI6yXH//PWwFcBNboMdKX6J0GtpZ3jo+N2o7R7P3m4TjVnFaeykWZIx/YtCX BvAOd+YU5nRULgJci+rbrl4B/Zg1uk528XX8XKiUor6ShIMzFwIrSuyGdT4aWblckwtG DxSg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=MGH/KEfo/NyZuIxXGMn5Co300AjgYW567euZkx3T6tY=; b=q0ONdCw+s1+uCpmRgZUi1qpPHQMh4GohmwQYK39lpmynRTYP2DIlXmw8OnAz/zU5YH XzCeyRLMPkmc7h8/ybwMY4gtC0HcgaWFmtsmk88DMRH6nAHX+ORYAfD1yA5D0+a3OD9N iCS/rPBFY2KVOmHlHGwf84dkeYZPZm7dakt+zwwptwq9k3e7Q107zvCsJmDMbIUGzlMq MM8XdfNr4k1pgqKLy3vcvpYycS+uaZAlvaCHEEBZrW9lulHcPpvdfaWf6mBY7Cb0xCHr ul1ZU1ckF3YR6uXiv27yeBxQTiOzBK2zNoDel4upHYpbZVQ3rmamtrnbHMF5L66rBjOv 0g6g== X-Gm-Message-State: AHPjjUgY4OmOciwZVwaK6mUAUYbSiFuR1qL5WjU4ECSMqXHUozo4NVvN +XUyI9PSLK0/Y2Xg8CkCxtU3UQ== X-Google-Smtp-Source: AOwi7QDtI/vr7QH3woQLVWjcc6s79XsQMQtshqaEV5VWrJdHwguHuwOmo/WdAcws4ldd/lyPe3C8iA== X-Received: by 10.84.132.66 with SMTP id 60mr421610ple.158.1506116390826; Fri, 22 Sep 2017 14:39:50 -0700 (PDT) Received: from ?IPv6:2601:640:103:944:cc86:8129:31f4:569e? ([2601:640:103:944:cc86:8129:31f4:569e]) by smtp.gmail.com with ESMTPSA id l66sm864365pfc.112.2017.09.22.14.39.49 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 22 Sep 2017 14:39:50 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 10.3 \(3273\)) From: Mark Friedenbach In-Reply-To: Date: Fri, 22 Sep 2017 14:39:45 -0700 Content-Transfer-Encoding: quoted-printable Message-Id: <9FD4AF03-28A5-4B8A-9C12-CBCB1BC2E22C@friedenbach.org> References: <5B6756D0-6BEF-4A01-BDB8-52C646916E29@friedenbach.org> <201709190309.08669.luke@dashjr.org> <3385CE20-C1BA-40DD-8FC3-8F53F3350717@friedenbach.org> To: Sergio Demian Lerner X-Mailer: Apple Mail (2.3273) X-Spam-Status: No, score=0.0 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, RCVD_IN_DNSWL_NONE autolearn=disabled version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org X-Mailman-Approved-At: Fri, 22 Sep 2017 21:42:22 +0000 Cc: Bitcoin Protocol Discussion Subject: Re: [bitcoin-dev] cleanstack alt stack & softfork improvements (Was: Merkle branch verification & tail-call semantics for generalized MAST) X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 22 Sep 2017 21:39:51 -0000 You generally know the witness size to within a few bytes right before = signing. Why would you not? You know the size of ECDSA signatures. You = can be told the size of a hash preimage by the other party. It takes = some contriving to come up with a scheme where one party has = variable-length signatures of their chosing > On Sep 22, 2017, at 2:32 PM, Sergio Demian Lerner = wrote: >=20 > But generally before one signs a transaction one does not know the = signature size (which may be variable). One can only estimate the = maximum size.=20