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 EB8211198 for ; Thu, 17 May 2018 16:56:40 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-vk0-f46.google.com (mail-vk0-f46.google.com [209.85.213.46]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 7AD7AA3 for ; Thu, 17 May 2018 16:56:40 +0000 (UTC) Received: by mail-vk0-f46.google.com with SMTP id q189-v6so3119885vkb.0 for ; Thu, 17 May 2018 09:56:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to; bh=UY2AbDn77xJI4sMgj7HR1XqdU5sltHR4vI3HIUynSls=; b=ekMLc86ae1lI4ijrNTjq4PftI2wM/tqXu/dqDl2E2pmF3oOulIq3CYCLd2K71Njtxi 0IgL/4s7W/yGVj5Gf4iGRCHRl6ObUyRnSxoRfT8mQl3XifsQs+hL08zzGK4ydcC5z/IF z6OVf6WFny/gUSSzhzJL147LJ6u8MI8zNdPfb5GBqNNs9b6nseD9eYE8TIZoM08zWAjb e3nQ9UVk/ZNcq2OJXbnO/fT0klHgq+qOUS5nhn2L1H6zyDwh30lwr5M2vQCCgAaZoDnY YOeko70NclwjGOCWmMyF0+74DRLdc26nxi4UzgQjiVCw2P3XTEO5eXHxGO5IwwJIlBkL CHmQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to; bh=UY2AbDn77xJI4sMgj7HR1XqdU5sltHR4vI3HIUynSls=; b=P9AIlxVf9fFQUdP6J6TWARSqLajUuYP84PbCmCNmJ2VukY96hIv+u56WuA8wXiL083 T5btoRnKQgyDteQP49+dW2AlwCW0rElm7elQvV2cuj0UBJkT0bq+Ue8g8D0ptwJy0UkO gX1KLqJBa+BLFHspIdRpDqSwQ4d3/ifwGgDV4nVb1pUKbXtVdh88cBqPm2n+i9zN+m5b djR3E88HSxkQytrec6ohMFOPAhLneHUxkWH1/igRo4k9gSA4k8Pb5oki53UZgtlpqKin A4y3bO0EzlPj0PBSfEef0Ge2a0XhEGj1pm9/syzM7pBiNot8fD1WupJhRASVWl1KmDdp ZHJQ== X-Gm-Message-State: ALKqPwc04W4/rjJXlK59VOvmEe7KYuHHkOM7BDDMBf7ArEe9kGR4L8l+ frNA+03ZdDBWhWMklp2Qjdi2XD10a6LZqNFUUrzpXA== X-Google-Smtp-Source: AB8JxZqW9qp7c9fbKZmvcZii4Mh3UsFVz76/dWCwdpWt/hETORWfIRGfYHacCIbL3lRsWQvIVzp2jCe/ZFfD9komOCQ= X-Received: by 2002:a1f:41cf:: with SMTP id o198-v6mr4533253vka.162.1526576199598; Thu, 17 May 2018 09:56:39 -0700 (PDT) MIME-Version: 1.0 Sender: gmaxwell@gmail.com Received: by 10.103.81.132 with HTTP; Thu, 17 May 2018 09:56:39 -0700 (PDT) In-Reply-To: References: From: Gregory Maxwell Date: Thu, 17 May 2018 16:56:39 +0000 X-Google-Sender-Auth: 2drMLBo7s3hNvqC0PpbKmXojt4c Message-ID: To: Cory Fields , Bitcoin Protocol Discussion Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, FREEMAIL_FROM, 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 Subject: Re: [bitcoin-dev] UHS: Full-node security without maintaining a full UTXO set 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: Thu, 17 May 2018 16:56:41 -0000 On Wed, May 16, 2018 at 4:36 PM, Cory Fields via bitcoin-dev wrote: > Tl;dr: Rather than storing all unspent outputs, store their hashes. My initial thoughts are it's not _completely_ obvious to me that a 5% ongoing bandwidth increase is actually a win to get something like a 40% reduction in the size of a pruned node (and less than a 1% reduction in an archive node) primarily because I've not seen size of a pruned node cited as a usage limiting factor basically anywhere. I would assume it is a win but wouldn't be shocked to see a careful analysis that concluded it wasn't. But perhaps more interestingly, I think the overhead is not really 5%, but it's 5% measured in the context of the phenomenally inefficient tx mechanisms ( https://bitcointalk.org/index.php?topic=1377345.0 ). Napkin math on the size of a txn alone tells me it's more like a 25% increase if you just consider size of tx vs size of tx+scriptpubkeys,amounts. If I'm not missing something there, I think that would get in into a very clear not-win range. On the positive side is that it doesn't change the blockchain datastructure, so it's something implementations could do without marrying the network to it forever.