From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1WTu6s-0006vw-Lw for bitcoin-development@lists.sourceforge.net; Sat, 29 Mar 2014 14:19:46 +0000 Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of bitpay.com designates 209.85.160.177 as permitted sender) client-ip=209.85.160.177; envelope-from=jgarzik@bitpay.com; helo=mail-yk0-f177.google.com; Received: from mail-yk0-f177.google.com ([209.85.160.177]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1WTu6r-00018H-Nx for bitcoin-development@lists.sourceforge.net; Sat, 29 Mar 2014 14:19:46 +0000 Received: by mail-yk0-f177.google.com with SMTP id q200so4646488ykb.22 for ; Sat, 29 Mar 2014 07:19:40 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-type:content-transfer-encoding; bh=6VQ3IYCog8sdIPmdtY1j5iojQaWc2vsrP9hhEHCAeQc=; b=WF6ULqv3Dsz4d6sZdeJTitRfnRKUB33mHdS3RMBv3e1UvZ4TB2loRdbiKrOHGHvrPB nWy0GbAAbk9Ihuuie/6W0KXfvocC337G+og4oButpUWNlRgx1EuM2Id8eDus09Uw9Trc 4kgPH8thD8WG5VnGzpdye3WQhp9+Xfpzat1aWepKnJj3006HykQxFU9S3gq4dB4GUy28 3ttI8LCkdmg1HWjoXd7XXxVbw1Eb6Gywncg/fln0yODtXVgbi8P3CeALLsmo0Htk4S3T 8yGDyFNc42t/mwCGuqajrewhWmM6TDUDiQfv/FOx1w4uMibyCMoIzTsVtCaIrvl+Q5zl kuYQ== X-Gm-Message-State: ALoCoQkMR09bAnYjOl0zFcYt4/cxcihkGNhr4Td7I+fWCtqIMztd7+ydJdNejJ1sxVXwQ1IG1uyc X-Received: by 10.236.125.12 with SMTP id y12mr20533957yhh.42.1396102780135; Sat, 29 Mar 2014 07:19:40 -0700 (PDT) MIME-Version: 1.0 Received: by 10.170.162.214 with HTTP; Sat, 29 Mar 2014 07:19:20 -0700 (PDT) In-Reply-To: <1894130.91FUH3Vu6n@crushinator> References: <1878927.J1e3zZmtIP@crushinator> <1894130.91FUH3Vu6n@crushinator> From: Jeff Garzik Date: Sat, 29 Mar 2014 10:19:20 -0400 Message-ID: To: Matt Whitlock Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable 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 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: 1WTu6r-00018H-Nx Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Presenting a BIP for Shamir's Secret Sharing of Bitcoin private keys 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: Sat, 29 Mar 2014 14:19:46 -0000 On Sat, Mar 29, 2014 at 10:10 AM, Matt Whitlock wro= te: > Multisig does not allow for the topology I described. Say the board has s= even directors, meaning the majority threshold is four. This means the orga= nization needs the consent of six individuals in order to sign a transactio= n: the president, the CFO, and any four of the board members. A 6-of-9 mult= isig would not accomplish the same policy, as then any six board members co= uld successfully sign a transaction without the consent of the president or= CFO. Of course the multi-signature scheme could be expanded to allow for h= ierarchical threshold topologies, or Shamir's Secret Sharing can be used to= distribute keys at the second level (and further, if desired). Disagree with "does not allow" Review bitcoin's script language. Bitcoin script can handle the use case you describe. Add conditionals to the bitcoin script, OP_IF etc. You can do 'multisig AND multisig' type boolean logic entirely in script, and be far more flexible than a single CHECKMULTISIG affords. --=20 Jeff Garzik Bitcoin core developer and open source evangelist BitPay, Inc. https://bitpay.com/