Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 807FC3BC5 for ; Wed, 31 Jul 2019 12:29:02 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from EUR03-AM5-obe.outbound.protection.outlook.com (mail-oln040092070014.outbound.protection.outlook.com [40.92.70.14]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 9F22CE7 for ; Wed, 31 Jul 2019 12:29:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=hotmail.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=pEf3GLD0l8SWqT6uYnBg9UGbs1Y/o3oFwbphRStEFoM=; b=bn+W7GT/XHiLsL0UyX4droYA1UcMtPIDtBaiCeHbdT/ZsmJDxKnDegb/2sLfCFrXxDd5XjVp+vF/CwjzfOJaYD7MTaZ3GJVHklvYATRa1SnFnoELn2wY6YuMBBTDK0ZpzDiyYmJB36EH18EiU815nnIxDCWOwW9LLzn5bYRPm+nbxOyUY6Eq6qd2Em2jFSTTPACuHBvR2lNbUv8faM6yMShhcBs0xNynTTMoTVLf0sfV86r08F8PCwwZYQefqaMOrozgyThsyk+xtzereqkID3ZzhPGMAL/BT6ubNZBbzJ/+chWHHr0pPE5Fsr1KdMr8x8CYpF9nW8/MhjGDqgz4xw== Received: from VE1EUR03FT045.eop-EUR03.prod.protection.outlook.com (10.152.18.59) by VE1EUR03HT008.eop-EUR03.prod.protection.outlook.com (10.152.18.127) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.20.2052.18; Wed, 31 Jul 2019 12:28:58 +0000 Received: from DB6PR10MB1832.EURPRD10.PROD.OUTLOOK.COM (10.152.18.58) by VE1EUR03FT045.mail.protection.outlook.com (10.152.19.51) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.20.2052.18 via Frontend Transport; Wed, 31 Jul 2019 12:28:58 +0000 Received: from DB6PR10MB1832.EURPRD10.PROD.OUTLOOK.COM ([fe80::cc12:47f0:aa33:6b70]) by DB6PR10MB1832.EURPRD10.PROD.OUTLOOK.COM ([fe80::cc12:47f0:aa33:6b70%3]) with mapi id 15.20.2115.005; Wed, 31 Jul 2019 12:28:58 +0000 From: "Kenshiro []" To: "bitcoin-dev@lists.linuxfoundation.org" Thread-Topic: Add a moving checkpoint to the Bitcoin protocol Thread-Index: AQHVR5sdyaW9NUkjL067/8euo+yr/A== Date: Wed, 31 Jul 2019 12:28:58 +0000 Message-ID: Accept-Language: en-US, es-ES Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-incomingtopheadermarker: OriginalChecksum:6E24234FECA2B9C89FE841E820A4C6805BBCE5A9B45B085A6A717DFB54F1F700; UpperCasedChecksum:8D488100C5302FB1331EBE57A61F29A952DD14CF1A2B98EB5A8CA11BDDA85D92; SizeAsReceived:6584; Count:40 x-tmn: [bTtA79fVNEKNiNFvH3UEAtsWnSobndi/] x-ms-publictraffictype: Email x-incomingheadercount: 40 x-eopattributedmessage: 0 x-microsoft-antispam: BCL:0; PCL:0; RULEID:(2390118)(5050001)(7020095)(20181119110)(201702061078)(5061506573)(5061507331)(1603103135)(2017031320274)(2017031322404)(2017031323274)(2017031324274)(1601125500)(1603101475)(1701031045); SRVR:VE1EUR03HT008; x-ms-traffictypediagnostic: VE1EUR03HT008: x-microsoft-antispam-message-info: gl4ssVlpR4eNp+IjMUhVG8Yao6UduWeUc/RX/wCGFNjZ/a4olB6sNVskE+iKG4ZOZzQJhicvrB2wpmF8UruvWHD8K/oEddc2tH5vNqh2ibU28hG/j7yFssx2CwEOo/pIYb/NfXZfGNLMW7Sw49BkCUYNT+E8Ap8o6Wvzax1GhSmL+bqfh22w2y8OCxy71ls2 Content-Type: multipart/alternative; boundary="_000_DB6PR10MB1832329BC8D151DC18F1E6CEA6DF0DB6PR10MB1832EURP_" MIME-Version: 1.0 X-OriginatorOrg: hotmail.com X-MS-Exchange-CrossTenant-RMS-PersistedConsumerOrg: 00000000-0000-0000-0000-000000000000 X-MS-Exchange-CrossTenant-Network-Message-Id: 5429f6de-7ad2-4f3b-c1c8-08d715b2a98d X-MS-Exchange-CrossTenant-rms-persistedconsumerorg: 00000000-0000-0000-0000-000000000000 X-MS-Exchange-CrossTenant-originalarrivaltime: 31 Jul 2019 12:28:58.7667 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Internet X-MS-Exchange-CrossTenant-id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa X-MS-Exchange-Transport-CrossTenantHeadersStamped: VE1EUR03HT008 X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM, HTML_MESSAGE, 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: Wed, 31 Jul 2019 13:17:33 +0000 Subject: [bitcoin-dev] Add a moving checkpoint to the Bitcoin protocol 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: Wed, 31 Jul 2019 12:29:02 -0000 --_000_DB6PR10MB1832329BC8D151DC18F1E6CEA6DF0DB6PR10MB1832EURP_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi all, I would like to propose that a "moving checkpoint" is added to the Bitcoin = protocol. It's a very simple rule already implemented in NXT coin: - A node will ignore any new block under nodeBlockHeight - N, so the blockc= hain becomes truly immutable after N blocks, even during a 51% attack which= thanks to the moving checkpoint can't rewrite history older than the last = N blocks. NXT coin has a N value of 720 blocks, like 12 hours of blocks. To be more conservative, Bitcoin could have a N value of 144 blocks (like 2= 4 hours). So users and exchanges could plan their operations with big amoun= ts of BTC knowing that only after 24 hours a transaction is truly immutable= . Maybe a 51% attack never happens but if it does it would be nice to be 100%= sure that history rewrite is limited to only 24 hours. Regards, --_000_DB6PR10MB1832329BC8D151DC18F1E6CEA6DF0DB6PR10MB1832EURP_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi all, 

I would like to propose that a "moving checkpoint" is added to th= e Bitcoin protocol. It's a very simple rule already implemented in NXT coin= : 

- A node will ignore any new block under nodeBlockHeight - N, so the b= lockchain becomes truly immutable after N blocks, even during a 51% attack = which thanks to the moving checkpoint can't rewrite history older than the = last N blocks.

NXT coin has a N value of 720 blocks, like 12 hours of blocks. 

To be more conservative, Bitcoin could have a N value of 144 blocks (like 2= 4 hours). So users and exchanges could plan their operations with big amoun= ts of BTC knowing that only after 24 hours a transaction is truly immutable= . 

Maybe a 51% attack never happens but if it does it would be nice to be 100%= sure that history rewrite is limited to only 24 hours.

Regards,
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