<oembed><type>rich</type><version>1.0</version><title>Antoine Riard [ARCHIVE] wrote</title><author_name>Antoine Riard [ARCHIVE] (npub1vj…4x8dd)</author_name><author_url>https://njump.me/npub1vjzmc45k8dgujppapp2ue20h3l9apnsntgv4c0ukncvv549q64gsz4x8dd</author_url><provider_name>njump</provider_name><provider_url>https://njump.me</provider_url><html>📅 Original date posted:2020-05-13&#xA;📝 Original message:Hi Chris,&#xA;&#xA;While approaching this question, I think you should consider economic&#xA;weight of nodes in evaluating miner consensus-hijack success. Even if you&#xA;expect a disproportionate ratio of full-nodes-vs-SPV, they may not have the&#xA;same  economic weight at all, therefore even if miners are able to lure a&#xA;majority of SPV clients they may not be able to stir economic nodes. SPV&#xA;clients users will now have an incentive to cancel their hijacked history&#xA;to stay on the most economic meaningful chain. And it&#39;s already assumed,&#xA;that if you run a bitcoin business or LN routing node, you do want to run&#xA;your own full-node.&#xA;&#xA;I agree it may be hard to evaluate economic-weight-to-chain-backend&#xA;segments, specially with offchain you disentangle an onchain output value&#xA;from its real payment traffic. To strengthen SPV, you may implement forks&#xA;detection and fallback to some backup node(s) which would serve as an&#xA;authoritative source to arbiter between branches. Such backup node(s) must&#xA;be picked up manually at client initialization, before any risk of conflict&#xA;to avoid Reddit-style of hijack during contentious period or other massive&#xA;social engineering. You don&#39;t want autopilot-style of recommendations for&#xA;picking up a backup nodes and avoid cenralization of backups, but somehow a&#xA;uniform distribution. A backup node may be a private one, it won&#39;t serve&#xA;you any data beyond headers, and therefore you preserve public nodes&#xA;bandwidth, which IMO is the real bottleneck. I concede it won&#39;t work well&#xA;if you have a ratio of 1000-SPV for 1-full-node and people are not&#xA;effectively able to pickup a backup among their social environment.&#xA;&#xA;What do you think about this model ?&#xA;&#xA;Cheers,&#xA;&#xA;Antoine&#xA;&#xA;Le mar. 12 mai 2020 à 17:06, Chris Belcher &lt;belcher at riseup.net&gt; a écrit :&#xA;&#xA;&gt; On 05/05/2020 16:16, Lloyd Fournier via bitcoin-dev wrote:&#xA;&gt; &gt; On Tue, May 5, 2020 at 9:01 PM Luke Dashjr via bitcoin-dev &lt;&#xA;&gt; &gt; bitcoin-dev at lists.linuxfoundation.org&gt; wrote:&#xA;&gt; &gt;&#xA;&gt; &gt;&gt; On Tuesday 05 May 2020 10:17:37 Antoine Riard via bitcoin-dev wrote:&#xA;&gt; &gt;&gt;&gt; Trust-minimization of Bitcoin security model has always relied first&#xA;&gt; and&#xA;&gt; &gt;&gt;&gt; above on running a full-node. This current paradigm may be shifted by&#xA;&gt; LN&#xA;&gt; &gt;&gt;&gt; where fast, affordable, confidential, censorship-resistant payment&#xA;&gt; &gt;&gt; services&#xA;&gt; &gt;&gt;&gt; may attract a lot of adoption without users running a full-node.&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&gt; No, it cannot be shifted. This would compromise Bitcoin itself, which&#xA;&gt; for&#xA;&gt; &gt;&gt; security depends on the assumption that a supermajority of the economy&#xA;&gt; is&#xA;&gt; &gt;&gt; verifying their incoming transactions using their own full node.&#xA;&gt; &gt;&gt;&#xA;&gt; &gt;&#xA;&gt; &gt; Hi Luke,&#xA;&gt; &gt;&#xA;&gt; &gt; I have heard this claim made several times but have never understood the&#xA;&gt; &gt; argument behind it. The question I always have is: If I get scammed by&#xA;&gt; not&#xA;&gt; &gt; verifying my incoming transactions properly how can this affect anyone&#xA;&gt; &gt; else? It&#39;s very unintuative.  I&#39;ve been scammed several times in my life&#xA;&gt; in&#xA;&gt; &gt; fiat currency transactions but as far as I could tell it never negatively&#xA;&gt; &gt; affected the currency overall!&#xA;&gt; &gt;&#xA;&gt; &gt; The links you point and from what I&#39;ve seen you say before refer to&#xA;&gt; &#34;miner&#xA;&gt; &gt; control&#34; as the culprit. My only thought is that this is because a light&#xA;&gt; &gt; client could follow a dishonest majority of hash power chain. But this&#xA;&gt; just&#xA;&gt; &gt; brings me back to the question. If, instead of BTC, I get a payment in&#xA;&gt; some&#xA;&gt; &gt; miner scamcoin on their dishonest fork (but I think it&#39;s BTC because I&#39;m&#xA;&gt; &gt; running a light client) that still seems to only to damage me. Where does&#xA;&gt; &gt; the side effect onto others on the network come from?&#xA;&gt; &gt;&#xA;&gt; &gt; Cheers,&#xA;&gt; &gt;&#xA;&gt; &gt; LL&#xA;&gt; &gt;&#xA;&gt;&#xA;&gt; Hello Lloyd,&#xA;&gt;&#xA;&gt; The problem comes when a large part of the ecosystem gets scammed at&#xA;&gt; once, which is how such an attack would happen in practice.&#xA;&gt;&#xA;&gt; For example, consider if bitcoin had 10000 users. 10 of them use a full&#xA;&gt; node wallet while the other 9990 use an SPV wallet. If a miner attacked&#xA;&gt; the system by printing infinite bitcoins and spending coins without a&#xA;&gt; valid signature, then the 9990 SPV wallets would accept those fake coins&#xA;&gt; as payment, and trade the coins amongst themselves. After a time those&#xA;&gt; coins would likely be the ancestors of most active coins in the&#xA;&gt; 9990-SPV-wallet ecosystem. Bitcoin would split into two currencies:&#xA;&gt; full-node-coin and SPV-coin.&#xA;&gt;&#xA;&gt; Now the fraud miners may become well known, perhaps being published on&#xA;&gt; bitcoin news portals, but the 9990-SPV-wallet ecosystem has a strong&#xA;&gt; incentive to be against any rollback. Their recent transactions would&#xA;&gt; disappear and they&#39;d lose money. They would argue that they&#39;ve already&#xA;&gt; been using the coin for a while, and it works perfectly fine, and anyway&#xA;&gt; a coin that can be spent in 9990 places is more useful than one that can&#xA;&gt; be spent in just 10 places. The SPV-wallet community might even decide&#xA;&gt; to use something like `invalidateblock` to make sure their SPV-coin&#xA;&gt; doesn&#39;t get reorg&#39;d out of existence. There&#39;d also likely be a social&#xA;&gt; attack, with every bitcoin community portal being flooded with bots and&#xA;&gt; shills advocating the merits of SPV-coin. This is not a hypothetical&#xA;&gt; because we already saw the same thing during the scalability conflict&#xA;&gt; 2015-2017.&#xA;&gt;&#xA;&gt; Before you know it, &#34;Bitcoin&#34; would become SPV-coin with inflation and&#xA;&gt; arbitrary seizure. Any normal user could download software called&#xA;&gt; &#34;Bitcoin wallet&#34; which they trust and have used before, but instead of&#xA;&gt; using Bitcoin they&#39;d be using SPV-coin. You may be one of the 10 wallets&#xA;&gt; backed by a full node, but that won&#39;t do much good to you when 9990&#xA;&gt; users happily use another coin as their medium of exchange.&#xA;&gt;&#xA;&gt; Regards&#xA;&gt; CB&#xA;&gt; _______________________________________________&#xA;&gt; Lightning-dev mailing list&#xA;&gt; Lightning-dev at lists.linuxfoundation.org&#xA;&gt; https://lists.linuxfoundation.org/mailman/listinfo/lightning-dev&#xA;&gt;&#xA;-------------- next part --------------&#xA;An HTML attachment was scrubbed...&#xA;URL: &lt;http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20200513/91739e5e/attachment.html&gt;</html></oembed>