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 4C09BCD3 for ; Tue, 12 Mar 2019 05:44:45 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from mo.garage.hdemail.jp (mo.garage.hdemail.jp [46.51.242.127]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 7D2AD2C4 for ; Tue, 12 Mar 2019 05:44:44 +0000 (UTC) Received: from ip-10-217-1-36.ap-northeast-1.compute.internal (localhost.localdomain [127.0.0.1]) by mo.garage.hdemail.jp (hde-mf-postfix) with SMTP id E7F2F14C0EC for ; Tue, 12 Mar 2019 14:44:42 +0900 (JST) (envelope-from karljohan-alm@garage.co.jp) X-Received: from unknown (HELO mo.garage.hdemail.jp) (127.0.0.1) by 0 with SMTP; 12 Mar 2019 14:44:42 +0900 X-Received: from mo.garage.hdemail.jp (localhost.localdomain [127.0.0.1]) by mo.garage.hdemail.jp (hde-ma-postfix) with ESMTP id DE2FA4C06D for ; Tue, 12 Mar 2019 14:44:42 +0900 (JST) (envelope-from karljohan-alm@garage.co.jp) Received: from gw22.oz.hdemail.jp (ip-10-127-175-123.ap-northeast-1.compute.internal [10.127.175.123]) by mo.garage.hdemail.jp (hde-mf-postfix) with ESMTP id D1DC114C0EC for ; Tue, 12 Mar 2019 14:44:42 +0900 (JST) (envelope-from karljohan-alm@garage.co.jp) X-Received: from mail-qt1-f197.google.com (lb05.oz.hdemail.jp [54.238.57.175]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by gw22.oz.hdemail.jp (Postfix) with ESMTP id 7A423148C10A for ; Tue, 12 Mar 2019 14:44:42 +0900 (JST) X-Received: by mail-qt1-f197.google.com with SMTP id e1so1228667qth.23 for ; Mon, 11 Mar 2019 22:44:42 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=dHi8mKzOAEIbCFkwGlykCSLDR/mr9oqXsP5f5OiBDmA=; b=oPJQ/V5AR09Pqn04v9dQJNRWmJpmjR9zhukv1UAzDNXUF2dfB8q5YhhYzoXe5tNk7T C50MIvvQGUb5lC2rQMn+Rq/P4WQUpuS58D0XqRIltzrSD6eCF5HYIwK6mBPqTluSg0l/ cpFj7scoadUtf+T6rF4Oftwvfg2jAjlBtAZGbWVI1V8v+ETgaWGAfUI27o+UGmyMjs+Y TLIGwX+1Ukm5cwvQB4T1YtDbb4j2Qqez5VIaKqZucAFLb8KFpGX/S4xRMiCdG1bsqvNB ECz48DCdg45zNtgwvtupJ2dIG8wXTgbZbZGPYCsq1UwPuBTOiuBrGGT5Ihzt4bkpfXC+ U/hg== X-Gm-Message-State: APjAAAXV4lM+y+LclXCpVHIuVr3O7QmhaAHIwZyrFoFuHjBMIZB6Qh3O RXI0DayiDs5lznMQeMgaib1a4vi3BWHwwyBe4ds+4s3Zi01P98o01jthvXV5wStLyRugyFB+obc +dPEnBFtEcPBbrX91CVMQOychzj/HHkvUXX8je2Qg7sv/0YaZsIJodliEMwfvwV9mcWX3VXkxa2 /10m2G/eKp5eZaD9w0uCr0RBmx9hHnvF7hv0fI6VHc1MUvCnN0xnOH9Y+7T43RAu+SAqop3kcvN IbmGLT6A7xuhx4jAafGWAGao+3CBpGq4V+fRTdQ9dRAEUzgPZBi8+ce6iKEI9XXEJLXxygTher2 uK+DsGkTM/fWtX6eyEY631Nvuqc= X-Received: by 2002:a05:620a:16b8:: with SMTP id s24mr26216486qkj.129.1552369480603; Mon, 11 Mar 2019 22:44:40 -0700 (PDT) X-Google-Smtp-Source: APXvYqzexmprzwU8iHmkxtJQSDpdbiktIn0+zT9L3Ht4IBM3C8Qqd+a1xL8BHDwGNltSpjUoAEppbF/3nURR3JBul/0= X-Received: by 2002:a05:620a:16b8:: with SMTP id s24mr26216474qkj.129.1552369480358; Mon, 11 Mar 2019 22:44:40 -0700 (PDT) MIME-Version: 1.0 References: <939C132D-8599-4258-8F14-62E992BA9F51@mattcorallo.com> <20190310170134.wtml7zuezfadb6hu@email> In-Reply-To: <20190310170134.wtml7zuezfadb6hu@email> From: Karl-Johan Alm Date: Tue, 12 Mar 2019 14:44:29 +0900 Message-ID: To: "David A. Harding" Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_NONE 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: Tue, 12 Mar 2019 05:45:36 +0000 Cc: Bitcoin Protocol Discussion Subject: Re: [bitcoin-dev] Signet X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 Mar 2019 05:44:45 -0000 Hello all, I started writing code that puts the signature in the coinbase transaction similar to the witness commitment, and encountered a potential issue. See inline comments below. On Mon, Mar 11, 2019 at 2:02 AM David A. Harding wrote: > > On Sun, Mar 10, 2019 at 09:43:43AM +0900, Karl-Johan Alm via bitcoin-dev wrote: > > Keeping the PoW rule and moving the signature would mean DoS attacks > > would be trivial as anyone could mine blocks without a signature in > > them > > Sure, but anyone could also just connect their lite client to a trusted > node (or nodes) on signet. The nodes would protect the clients from > missing/invalid-signature DoS and the clients wouldn't have to implement > any more network-level changes than they need to now for testnet. > > For people who don't want to run their own trusted signet nodes, there > could be a list of signet nodes run by well-known Bitcoiners (and this > could even be made available via a simple static dns seeder lite clients > could use). This sounds sensible. One issue here is that the "proper" signer will be orders of magnitude slower than the fake miner when constructing blocks. Because the signature is now stuffed into the coinbase transaction, it becomes a part of the block merkle root, so the true miner now has to (1) create a block, (2) sign it, (3) check if hash < target, (4) nudge nonce if not, and then repeat from step (2) until it finds a valid block. I.e. it has to sign the entire thing for every nonce. > This post from Maxwell could be the idea Corallo is describing: > > https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-August/016348.html That's pretty cool. The plan I had was to set up some simple interface where anyone could "order" reorgs whenever they wanted to. It would reorg/double spend people on request (e.g. "send 1 signetcoin to signet1qfoobar and then double spend it in a reorg 3 blocks deep") and so on. With that kind of tool, I don't know if you need the alternate signing approach you described, but I could be mistaken.