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-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1YEQrx-0002a4-Jo for bitcoin-development@lists.sourceforge.net; Thu, 22 Jan 2015 23:08:57 +0000 X-ACL-Warn: Received: from mail-pa0-f48.google.com ([209.85.220.48]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:RC4-SHA:128) (Exim 4.76) id 1YEQrw-00022h-Fg for bitcoin-development@lists.sourceforge.net; Thu, 22 Jan 2015 23:08:57 +0000 Received: by mail-pa0-f48.google.com with SMTP id ey11so4744058pad.7 for ; Thu, 22 Jan 2015 15:08:51 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=M/8Jr0xTN0nNFE18ZqAZQdbYkqWvRVTbasEk0v2e0YY=; b=S1uezsYwIx8G/Q/oXn6PLmr4i1udO0UIFoXPg7Oxg72x5jTbGMeNUNS6MM4A8s94vm aG/9jsjeZqQYgwjAJ7UxQE7Yr5BPwocYpQQBnE0OeiH06Y4ZKc3iZKintwWlwvdMokbU JErcYm6CK3JkF2vZf3iIjyTrxlxl1yyi/1H1SwSrBa8o9dgTz6XAt6Mbc1f30tPMREfi Ljm9UWjxWRcYTNgu1N1PATLHeMf2n4PRU9DsMHUseFBaJ+7bwgYg2NLH/lK9L5L+w55o zE02LxtXh870U8ptnqjUqxuy7pHbLSt7Kr75Gc/YyIPHa2YDI9ERFDoUpGE/a2VmFZtj ryRw== X-Gm-Message-State: ALoCoQnnZY2DvKnms3vVhplyjsKWm2oAdZzHH/OxTIVsb49Jr8q3e3UdNxiu+LFgMEZKSEic3F1l MIME-Version: 1.0 X-Received: by 10.70.98.200 with SMTP id ek8mr5732341pdb.163.1421966507370; Thu, 22 Jan 2015 14:41:47 -0800 (PST) Received: by 10.70.51.130 with HTTP; Thu, 22 Jan 2015 14:41:47 -0800 (PST) In-Reply-To: References: Date: Thu, 22 Jan 2015 22:41:47 +0000 Message-ID: From: Zooko Wilcox-OHearn To: Pieter Wuille Content-Type: text/plain; charset=UTF-8 X-Spam-Score: 0.0 (/) X-Spam-Report: Spam Filtering performed by mx.sourceforge.net. See http://spamassassin.org/tag/ for more details. X-Headers-End: 1YEQrw-00022h-Fg 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: Thu, 22 Jan 2015 23:08:57 -0000 .Hi there. Thank you for your work on this. I've looked over https://gist.github.com/sipa/5d12c343746dad376c80 and https://github.com/sipa/bitcoin/commit/bipstrictder . I didn't actually audit the included reference implementation of IsValidSignatureEncoding(), and I didn't check whether the test vectors in https://github.com/sipa/bitcoin/commit/f94e806f8bfa007a3de4b45fa3c9860f2747e427 exercise all of the branches that are changed by this patch. I have the following comments: * It seems like a good idea to do this. * I don't see any problem with using the upgrade mechanism from BIP 34 for this. It's cool! I'm happy that such a mechanism seems to work in practice. * Should the bipstrictder give a rationale or link to why accept the 0-length sig as correctly-encoded-but-invalid? I guess the rationale is an efficiency issue as described in the log entry for https://github.com/sipa/bitcoin/commit/041f1e3597812c250ebedbd8f4ef1565591d2c34 . * Does this mean there are still multiple ways to encode a correctly encoded but invalid signature, one of which is the 0-length string? Would it make sense for this change to also treat any *other* correctly-encoded-but-invalid sig (besides the 0-length string) as incorrectly-encoded? Did I just step in some BIP62? * It would be good to verify that all the branches of the new IsDERSignature() from https://github.com/sipa/bitcoin/commit/0c427135151a6bed657438ffb2e670be84eb3642 are tested by the test vectors in https://github.com/sipa/bitcoin/commit/f94e806f8bfa007a3de4b45fa3c9860f2747e427 . Eyeballing it, there are about 20 branches touched by the patch, and about 24 new test vectors. * It would be good to finish the TODOs in https://github.com/sipa/bitcoin/commit/b7986119a5d41337fea1e83804ed6223438158ec so that it was actually testing the upgrade behavior. * missing comment: https://github.com/sipa/bitcoin/commit/e186f6a80161f9fa45fbced82ab1d22f081b942c#commitcomment-9406643 Okay, that's all I've got. Hope it helps! Thanks again for your good work! Regards, Zooko