<div dir="auto"><div dir="auto">What about periodically committing the entire UTXO set to a special checkpoint block which becomes the new de facto Genesis block? </div><div dir="auto"><br></div><div dir="auto">Daniele </div><div dir="auto"><br></div><div dir="auto"><span style="font-family:sans-serif;font-size:13.696px">------------------------------</span><br style="font-family:sans-serif;font-size:13.696px"><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">Message: 5</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">Date: Wed, 29 Mar 2017 16:41:29 +0000</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">From: Andrew Johnson &lt;</span><a href="mailto:andrew.johnson83@gmail.com" style="text-decoration:none;color:rgb(66,133,244);font-family:sans-serif;font-size:13.696px">andrew.johnson83@gmail.com</a><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">To: David Vorick &lt;</span><a href="mailto:david.vorick@gmail.com" style="text-decoration:none;color:rgb(66,133,244);font-family:sans-serif;font-size:13.696px">david.vorick@gmail.com</a><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">Cc: Bitcoin Dev &lt;</span><a href="mailto:bitcoin-dev@lists.linuxfoundation.org" style="text-decoration:none;color:rgb(66,133,244);font-family:sans-serif;font-size:13.696px">bitcoin-dev@lists.<wbr>linuxfoundation.org</a><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">Subject: Re: [bitcoin-dev] Hard fork proposal from last week&#39;s meeting</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">Message-ID:</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">        &lt;</span><a href="mailto:CAAy62_%2BJtoAuM-RsrAAp5eiGiO%2BOHLDjzqgbnF2De7TUU7TyYg@mail.gmail.com" style="text-decoration:none;color:rgb(66,133,244);font-family:sans-serif;font-size:13.696px">CAAy62_+JtoAuM-RsrAAp5eiGiO+<wbr>OHLDjzqgbnF2De7TUU7TyYg@mail.<wbr>gmail.com</a><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">Content-Type: text/plain; charset=&quot;utf-8&quot;</span><br style="font-family:sans-serif;font-size:13.696px"><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">I believe that as we continue to add users to the system by scaling</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">capacity that we will see more new nodes appear, but I&#39;m at a bit of a loss</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">as to how to empirically prove it.</span><br style="font-family:sans-serif;font-size:13.696px"><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">I do see your point on increasing load on archival nodes, but the majority</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">of that load is going to come from new nodes coming online, they&#39;re the</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">only ones going after very old blocks.   I could see that as a potential</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">attack vector, overwhelm the archival nodes by spinning up new nodes</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">constantly, therefore making it difficult for a &quot;real&quot; new node to get up</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">to speed in a reasonable amount of time.</span><br style="font-family:sans-serif;font-size:13.696px"><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">Perhaps the answer there would be a way to pay an archival node a small</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">amount of bitcoin in order to retrieve blocks older than a certain cutoff?</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">Include an IP address for the node asking for the data as metadata in the</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">transaction...  Archival nodes could set and publish their own policy, let</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">the market decide what those older blocks are worth.  Would also help to</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">incentivize running archival node, which we do need.  Of course, this isn&#39;t</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">very user friendly.</span><br style="font-family:sans-serif;font-size:13.696px"><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">We can take this to bitcoin-discuss, if we&#39;re getting too far off topic.</span><br style="font-family:sans-serif;font-size:13.696px"><br style="font-family:sans-serif;font-size:13.696px"><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">On Wed, Mar 29, 2017 at 11:25 AM David Vorick &lt;</span><a href="mailto:david.vorick@gmail.com" style="text-decoration:none;color:rgb(66,133,244);font-family:sans-serif;font-size:13.696px">david.vorick@gmail.com</a><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">wrote:</span><br style="font-family:sans-serif;font-size:13.696px"><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt; On Mar 29, 2017 12:20 PM, &quot;Andrew Johnson&quot; &lt;</span><a href="mailto:andrew.johnson83@gmail.com" style="text-decoration:none;color:rgb(66,133,244);font-family:sans-serif;font-size:13.696px">andrew.johnson83@gmail.com</a><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt; wrote:</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt; What&#39;s stopping these users from running a pruned node?  Not every node</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt; needs to store a complete copy of the blockchain.</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt; Pruned nodes are not the default configuration, if it was the default</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt; configuration then I think you would see far more users running a pruned</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt; node.</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt; But that would also substantially increase the burden on archive nodes.</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt; Further discussion about disk space requirements should be taken to</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt; another thread.</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">&gt; --</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">Andrew Johnson</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">-------------- next part --------------</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">An HTML attachment was scrubbed...</span><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">URL: &lt;</span><a href="http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20170329/9b48ebe3/attachment.html" style="text-decoration:none;color:rgb(66,133,244);font-family:sans-serif;font-size:13.696px">http://lists.linuxfoundation.<wbr>org/pipermail/bitcoin-dev/<wbr>attachments/20170329/9b48ebe3/<wbr>attachment.html</a><span style="font-family:sans-serif;font-size:13.696px">&gt;</span><br style="font-family:sans-serif;font-size:13.696px"><br style="font-family:sans-serif;font-size:13.696px"><span style="font-family:sans-serif;font-size:13.696px">------------------------------</span><br style="font-family:sans-serif;font-size:13.696px"></div></div>