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 1WTufx-00083x-CI for bitcoin-development@lists.sourceforge.net; Sat, 29 Mar 2014 14:56:01 +0000 X-ACL-Warn: Received: from qmta07.westchester.pa.mail.comcast.net ([76.96.62.64]) by sog-mx-1.v43.ch3.sourceforge.com with esmtp (Exim 4.76) id 1WTufw-00028K-ER for bitcoin-development@lists.sourceforge.net; Sat, 29 Mar 2014 14:56:01 +0000 Received: from omta17.westchester.pa.mail.comcast.net ([76.96.62.89]) by qmta07.westchester.pa.mail.comcast.net with comcast id jSM61n0041vXlb857Svvp3; Sat, 29 Mar 2014 14:55:55 +0000 Received: from crushinator.localnet ([IPv6:2601:6:4800:47f:219:d1ff:fe75:dc2f]) by omta17.westchester.pa.mail.comcast.net with comcast id jSvu1n0064VnV2P3dSvume; Sat, 29 Mar 2014 14:55:55 +0000 From: Matt Whitlock To: Jeff Garzik Date: Sat, 29 Mar 2014 10:55:54 -0400 Message-ID: <4113697.13qtlTpVUA@crushinator> User-Agent: KMail/4.12.3 (Linux/3.12.13-gentoo; KDE/4.12.3; x86_64; ; ) In-Reply-To: References: <1878927.J1e3zZmtIP@crushinator> <1894130.91FUH3Vu6n@crushinator> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Spam-Score: 0.0 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [76.96.62.64 listed in list.dnswl.org] 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: 1WTufw-00028K-ER 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 14:56:01 -0000 On Saturday, 29 March 2014, at 10:19 am, Jeff Garzik wrote: > On Sat, Mar 29, 2014 at 10:10 AM, Matt Whitlock wrote: > > Multisig does not allow for the topology I described. Say the board has seven directors, meaning the majority threshold is four. This means the organization needs the consent of six individuals in order to sign a transaction: the president, the CFO, and any four of the board members. A 6-of-9 multisig would not accomplish the same policy, as then any six board members could successfully sign a transaction without the consent of the president or CFO. Of course the multi-signature scheme could be expanded to allow for hierarchical 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. Depends on your definition of "can." Bitcoin's scripting language is awesome, but it's mostly useless due to the requirement that scripts match one of a select few "standard" templates in order to be allowed to propagate across the network and be mined into blocks. I really hate IsStandard and wish it would die.