Received: from sog-mx-3.v43.ch3.sourceforge.com ([172.29.43.193] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1XPDW4-0002UK-3w for bitcoin-development@lists.sourceforge.net; Wed, 03 Sep 2014 16:34:40 +0000 Received-SPF: pass (sog-mx-3.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.213.173 as permitted sender) client-ip=209.85.213.173; envelope-from=pieter.wuille@gmail.com; helo=mail-ig0-f173.google.com; Received: from mail-ig0-f173.google.com ([209.85.213.173]) by sog-mx-3.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1XPDW3-00041S-73 for bitcoin-development@lists.sourceforge.net; Wed, 03 Sep 2014 16:34:40 +0000 Received: by mail-ig0-f173.google.com with SMTP id h18so1128706igc.12 for ; Wed, 03 Sep 2014 09:34:34 -0700 (PDT) MIME-Version: 1.0 X-Received: by 10.50.61.138 with SMTP id p10mr39035087igr.20.1409762073926; Wed, 03 Sep 2014 09:34:33 -0700 (PDT) Received: by 10.50.82.72 with HTTP; Wed, 3 Sep 2014 09:34:33 -0700 (PDT) In-Reply-To: References: Date: Wed, 3 Sep 2014 18:34:33 +0200 Message-ID: From: Pieter Wuille To: Gregory Maxwell Content-Type: text/plain; charset=ISO-8859-1 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 (pieter.wuille[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: 1XPDW3-00041S-73 Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Small update to BIP 62 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, 03 Sep 2014 16:34:40 -0000 On Mon, Sep 1, 2014 at 10:48 PM, Gregory Maxwell wrote: > Not related to this change but the definition of rule 4 may not be > sufficiently specific-- without a definition someone could reasonably > reach a different conclusion about OP_1NEGATE being a "push > operation", or might even decide any operation which added to the > stack was a "push operation". Good catch - I'll write an update soon. > Any particular reason to enforce 2 and 4 but not also 5? Violation of > 5 is already non-standard and like 2,4 should be safely enforceable. Perhaps we can go further, and include 6 as well? I see zero use cases for zero-padded numbers, as their interpretation is already identical to the non-padded case. I wouldn't include 1 (as it would break a large amount of wallets today), 3 (which may have a use case in more complex scripts with conditionals) or 7 (the superfluous element consumed by CHECKMULTISIG could potentially be used for something in the future). > Perhaps the rules should be reordered so that the applicable to all > transactions ones are contiguous and first? Ok. >> The first six and part of the seventh can be fixed by extra consensus rules. > > This should clarify that the scriptPubkey can still specify rules that > are inherently malleable-- e.g. require the input stack contain two > pushes which OP_ADD to 11. Or a more elaborate one-- a 1 of 2 check > multisig where the pubkey not selected for signing is selected by a > push in the signature. The current text seems to ignore isomorphisms > of this type. ... they're not important for what the BIP is trying to > achieve, but the document shouldn't cause people to not think that > sort of thing exists. I'll try to reword. -- Pieter