From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 467A3C30 for ; Fri, 26 Feb 2016 02:03:09 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-pf0-f180.google.com (mail-pf0-f180.google.com [209.85.192.180]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id D453A141 for ; Fri, 26 Feb 2016 02:03:08 +0000 (UTC) Received: by mail-pf0-f180.google.com with SMTP id c10so44385809pfc.2 for ; Thu, 25 Feb 2016 18:03:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lightning.network; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to; bh=w+E/P7QksoHpMn/Gbzbee9ObCTlUM6WJpBB2sGXm+s8=; b=StDyLndL5WZp8oUezu2luomhFqWNnIVLZm4tR2aOM+RP8j5L5Li+v0usN8xXEBauDt Y+bB5/WSIsuNJ8MAXWHCk6oivp18kmg9Oh1ckmEvT6nSwI3L7XNNmfppa8qODD86URrI pXywOo+2H6FrAMruwNW46fk42XFoJnNswgL7I= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-type:content-disposition:in-reply-to; bh=w+E/P7QksoHpMn/Gbzbee9ObCTlUM6WJpBB2sGXm+s8=; b=BcLSlo+a2DCxs6n3qW7MJgj1T5S6gYZtlRVA2IqvhrMNqb3JeJLwqvjmyvOvJtsfWE h/7XnsTPrIj5G/ArrSbyr+zUlZyGNJJqeNYdvu26gyWbcsdBGKBQIXo3Oe5OK8w6qNvn 8iHxOQVIt9bVguc06DggpxURXESa+L0JYm+s3+iRlgf8hwt3Ku92IZEFUUO0lNeWmjZa CF//RtD2/ynVZ3KlBZbuETBt0yfMKDRJly8JHq+ylnP/fgozK9DNmMSRE3r+9EDHlskk bu+D4CqG7u2s3z9t2/6ea8nF2O6BoIE41wPoaOEePHTL8VAk16Y6jNxIIs0JIHaFa73Z LIWg== X-Gm-Message-State: AG10YOTDLCuX/Lor1EpCTMXbcbDmNfbktOzv7IsKBOyr5zA7MzotJ1sjHk0BMLXQeQgL8w== X-Received: by 10.98.42.150 with SMTP id q144mr62414905pfq.73.1456452188618; Thu, 25 Feb 2016 18:03:08 -0800 (PST) Received: from localhost ([2605:6400:20:11aa:189e:28a5:52ed:8948]) by smtp.gmail.com with ESMTPSA id t87sm14929990pfa.14.2016.02.25.18.03.07 (version=TLSv1/SSLv3 cipher=OTHER); Thu, 25 Feb 2016 18:03:08 -0800 (PST) Date: Thu, 25 Feb 2016 18:02:26 -0800 From: Joseph Poon To: Bryan Bishop Message-ID: <20160226020226.GA25101@lightning.network> References: <20160226010746.GB10295@lightning.network> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org X-Mailman-Approved-At: Fri, 26 Feb 2016 03:13:08 +0000 Cc: Bitcoin Dev , lightning-dev Subject: Re: [bitcoin-dev] SIGHASH_NOINPUT in Segregated Witness X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Development Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 26 Feb 2016 02:03:09 -0000 Hi Bryan, On Thu, Feb 25, 2016 at 07:34:24PM -0600, Bryan Bishop wrote: > Well if you are bothering to draft up a BIP about that SIGHASH flag, > then perhaps also consider some other SIGHASH flag types as well while > you are at it? I'll take a look at those proposals when drafting the BIP. I think for LN, there is a single clean way to achieve outsourcability, but may be compatible with other arrangements. I'm somewhat averse to proposing too much flexibility before there's clear use-cases, though. However, if others do have uses/examples for other sighash flags, I'd be very interested while drafting this BIP! > FWIW there was some concern about replay using SIGHAHS_NOINPUT or something: > http://gnusha.org/bitcoin-wizards/2015-04-07.log Yeah, I think the nice thing about SegWit is that you resolve malleability without worrying about replay attacks in the event of key reuse. That's why I think it's only safe to do this new sighash type inside segwit itself -- if you only wanted protection against malleability you'd use segwit, and not touch this new sighash type (you'd only use the new sighash flag if you actually need its features). -- Joseph Poon