From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <luke@dashjr.org>
Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org
	[172.17.192.35])
	by mail.linuxfoundation.org (Postfix) with ESMTPS id 9A8F598F
	for <bitcoin-dev@lists.linuxfoundation.org>;
	Wed, 20 Jul 2016 06:17:56 +0000 (UTC)
X-Greylist: from auto-whitelisted by SQLgrey-1.7.6
Received: from zinan.dashjr.org (unknown [192.3.11.21])
	by smtp1.linuxfoundation.org (Postfix) with ESMTP id 49D0E7D
	for <bitcoin-dev@lists.linuxfoundation.org>;
	Wed, 20 Jul 2016 06:17:56 +0000 (UTC)
Received: from ishibashi.localnet (unknown
	[IPv6:2001:470:5:265:61b6:56a6:b03d:28d6])
	(Authenticated sender: luke-jr)
	by zinan.dashjr.org (Postfix) with ESMTPSA id C8D4738A17CC;
	Wed, 20 Jul 2016 06:17:41 +0000 (UTC)
X-Hashcash: 1:25:160720:bitcoin-dev@lists.linuxfoundation.org::P7PT5665Be=tk0f/:Kt9V
X-Hashcash: 1:25:160720:pete@petertodd.org::MxM72nS+KKvh9mzP:apYRW
X-Hashcash: 1:25:160720:sean@z.cash::Zd8/fZU83odZV7bU:ogHB
From: Luke Dashjr <luke@dashjr.org>
To: bitcoin-dev@lists.linuxfoundation.org,
 Peter Todd <pete@petertodd.org>
Date: Wed, 20 Jul 2016 06:17:39 +0000
User-Agent: KMail/1.13.7 (Linux/4.1.18-gentoo; KDE/4.14.16; x86_64; ; )
References: <CAKazn3mKUMMz0wyqTsgbkd4mBLgvG2PXziXhgRTi4hX_ApbPhg@mail.gmail.com>
	<20160720054654.GA1420@fedora-21-dvm>
In-Reply-To: <20160720054654.GA1420@fedora-21-dvm>
X-PGP-Key-Fingerprint: E463 A93F 5F31 17EE DE6C 7316 BD02 9424 21F4 889F
X-PGP-Key-ID: BD02942421F4889F
X-PGP-Keyserver: hkp://pgp.mit.edu
MIME-Version: 1.0
Content-Type: Text/Plain;
  charset="iso-8859-15"
Content-Transfer-Encoding: 7bit
Message-Id: <201607200617.40917.luke@dashjr.org>
X-Spam-Status: No, score=-0.9 required=5.0 tests=BAYES_00,RDNS_DYNAMIC
	autolearn=no version=3.3.1
X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on
	smtp1.linux-foundation.org
Subject: Re: [bitcoin-dev] BIP draft: HTLC transactions
X-BeenThere: bitcoin-dev@lists.linuxfoundation.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Bitcoin Protocol Discussion <bitcoin-dev.lists.linuxfoundation.org>
List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/bitcoin-dev>,
	<mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=unsubscribe>
List-Archive: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/>
List-Post: <mailto:bitcoin-dev@lists.linuxfoundation.org>
List-Help: <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=help>
List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>,
	<mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=subscribe>
X-List-Received-Date: Wed, 20 Jul 2016 06:17:56 -0000

On Wednesday, July 20, 2016 5:46:54 AM Peter Todd via bitcoin-dev wrote:
> On Tue, Jul 19, 2016 at 10:35:39PM -0600, Sean Bowe via bitcoin-dev wrote:
> > I'm requesting feedback for Hash Time-Locked Contract (HTLC) transactions
> > in Bitcoin.
> > 
> > HTLC transactions allow you to pay for the preimage of a hash. CSV/CLTV
> > can be used to recover your funds if the other party is not cooperative.
> > These
> > 
> > scripts take the following general form:
> >     [HASHOP] <digest> OP_EQUAL
> >     OP_IF
> >     
> >         <seller pubkey>
> >     
> >     OP_ELSE
> >     
> >         <num> [TIMEOUTOP] OP_DROP <buyer pubkey>
> >     
> >     OP_ENDIF
> >     OP_CHECKSIG
> 
> Note that because you're hashing the top item on the stack regardless
> scriptSig's that satisfy HTLC's are malleable: that top stack item can be
> changed anything in the digest-not-provided case and the script still
> passes.

OP_SIZE
OP_IF
  [HASHOP] <digest> OP_EQUALVERIFY
  <seller pubkey>
OP_ELSE
  <num> [TIMEOUTOP]
  <buyer pubkey>
OP_ENDIF
OP_CHECKSIG