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-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1YE1vO-0002Ux-RB for bitcoin-development@lists.sourceforge.net; Wed, 21 Jan 2015 20:30:50 +0000 Received-SPF: pass (sog-mx-1.v43.ch3.sourceforge.com: domain of gmail.com designates 209.85.223.175 as permitted sender) client-ip=209.85.223.175; envelope-from=pieter.wuille@gmail.com; helo=mail-ie0-f175.google.com; Received: from mail-ie0-f175.google.com ([209.85.223.175]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1YE1vO-0003xl-1i for bitcoin-development@lists.sourceforge.net; Wed, 21 Jan 2015 20:30:50 +0000 Received: by mail-ie0-f175.google.com with SMTP id ar1so12763261iec.6 for ; Wed, 21 Jan 2015 12:30:44 -0800 (PST) MIME-Version: 1.0 X-Received: by 10.43.140.68 with SMTP id iz4mr3373968icc.77.1421872244788; Wed, 21 Jan 2015 12:30:44 -0800 (PST) Received: by 10.50.20.229 with HTTP; Wed, 21 Jan 2015 12:30:44 -0800 (PST) In-Reply-To: <54BFFE30.8010105@bitcoinarmory.com> References: <54BFFE30.8010105@bitcoinarmory.com> Date: Wed, 21 Jan 2015 15:30:44 -0500 Message-ID: From: Pieter Wuille To: Douglas Roark 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: 1YE1vO-0003xl-1i Cc: Bitcoin Dev Subject: Re: [Bitcoin-development] [softfork proposal] Strict DER signatures 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, 21 Jan 2015 20:30:50 -0000 On Wed, Jan 21, 2015 at 2:29 PM, Douglas Roark wrote: > Nice paper, Pieter. I do have a bit of feedback. Thanks for the comments. I hope I have clarified the text a bit accordingly. > 1)The first sentence of "Deployment" has a typo. "We reuse the > double-threshold switchover mechanism from BIP 34, with the same > *thresholds*, [....]" Fixed. > 2)I think the handling of the sighash byte in the comments of > IsDERSignature() could use a little tweaking. If you look at > CheckSignatureEncoding() in the actual code (src/script/interpreter.cpp > in master), it's clear that the sighash byte is included as part of the > signature struct, even though it's not part of the actual DER encoding > being checked by IsDERSignature(). This is fine. I just think that the > code comments in the paper ought to make this point clearer, either in > the sighash description, or as a comment when checking the sig size > (i.e., size-3 is valid because sighash is included), or both. I've renamed the function to IsValidSignatureEncoding, as it is not strictly about DER (it adds a Bitcoin-specific byte, and supports and empty string too). > 3)The paper says a sig with size=0 is correctly coded but is neither > valid nor DER. Perhaps this code should be elsewhere in the Bitcoin > code? It seems to me that letting a sig pass in IsDERSignature() when > it's not actually DER-encoded is incorrect. I've expanded the comments about it a bit. -- Pieter