From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1XqKyc-0003z0-1S for bitcoin-development@lists.sourceforge.net; Mon, 17 Nov 2014 12:00:14 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.213.180 as permitted sender) client-ip=209.85.213.180; envelope-from=pieter.wuille@gmail.com; helo=mail-ig0-f180.google.com; Received: from mail-ig0-f180.google.com ([209.85.213.180]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1XqKyb-0002ZR-7Z for bitcoin-development@lists.sourceforge.net; Mon, 17 Nov 2014 12:00:14 +0000 Received: by mail-ig0-f180.google.com with SMTP id h15so4978214igd.13 for ; Mon, 17 Nov 2014 04:00:08 -0800 (PST) MIME-Version: 1.0 X-Received: by 10.107.137.84 with SMTP id l81mr2014604iod.61.1416225607886; Mon, 17 Nov 2014 04:00:07 -0800 (PST) Received: by 10.50.248.5 with HTTP; Mon, 17 Nov 2014 04:00:07 -0800 (PST) In-Reply-To: References: <201411161724.19573.luke@dashjr.org> <5469692F.9030702@gmail.com> Date: Mon, 17 Nov 2014 13:00:07 +0100 Message-ID: From: Pieter Wuille To: Flavien Charlon 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: 1XqKyb-0002ZR-7Z Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] Increasing the OP_RETURN maximum payload size 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: Mon, 17 Nov 2014 12:00:14 -0000 On Mon, Nov 17, 2014 at 12:43 PM, Flavien Charlon wrote: >> My main concern with OP_RETURN is that it seems to encourage people to use >> the blockchain as a convenient transport channel > > The number one user of the blockchain as a storage and transport mechanism > is Counterparty, and limiting OP_RETURN to 40 bytes didn't prevent them from > doing so. In fact they use multi-sig outputs which is worse than OP_RETURN > since it's not always prunable, and yet let them store much more than 40 > bytes. It wasn't limited to stop them from using it. It was limited to avoid giving others the impression that OP_RETURN was intended for data storage. For the intended purpose (making a transaction commit to some external data) a 32-byte hash + 8 byte id is more than sufficient. > For Open Assets, we need to store a URL in the OP_RETURN output (with > optionally a hash) plus some bytes of overhead. 40 bytes comes really short > for that. The benefit of having a URL in there is that any storage mechanism > can be used (Web, FTP, BitTorrent, MaidSafe...), whereas with only a hash, > you have to hardcode the storing mechanism in the protocol (and even then, a > hash is not enough to address a HTTP or FTP resource). Storing only a hash > is fine for the most basic timestamping application, but it's hardly enough > to build something interesting. Do you really need that data published to everyone? You're at the very least exposing yourself to censorship, and (depending on the design) potentially decreased privacy for your users. I would expect that for most colored coin applications, just having the color transfer information in external data sent directly to the receiver with transactions committing to it should suffice. -- Pieter