<oembed><type>rich</type><version>1.0</version><author_name>npub1k6906yrdzekdkn23mrskcf6up8s2fypqldhnz9gfc44kwsan02zq5xvja6</author_name><author_url>https://nostr.ae/npub1k6906yrdzekdkn23mrskcf6up8s2fypqldhnz9gfc44kwsan02zq5xvja6</author_url><provider_name>njump</provider_name><provider_url>https://nostr.ae</provider_url><html>📅 Original date posted:2015-12-28&#xA;📝 Original message:On Mon, Dec 28, 2015 at 2:12 PM, Peter Todd via bitcoin-dev &lt;&#xA;bitcoin-dev at lists.linuxfoundation.org&gt; wrote:&#xA;&#xA;&gt; Do you specifically mean selfish mining as defined in Emin Gün&#xA;&gt; Sirer/Ittay Eyal&#39;s paper? Keep in mind that attack is only a significant&#xA;&gt; issue in a scenario - one malicious miner with &gt;30% hashing power -&#xA;&gt; where you&#39;re already very close to the margins anyway; the difference&#xA;&gt; between a 50% attack threshold and a 30% attack threshold isn&#39;t very&#xA;&gt; significant.&#xA;&gt;&#xA;&#xA;This is not quite right: we know that selfish mining is a guaranteed win&#xA;at 34%. We do not know when exactly it begins to pay off. The more&#xA;consolidated and centralized the other mining pools, the less of a threat&#xA;it is below 34%; the more decentralized, the more likely it is to pay off&#xA;at lower thresholds.&#xA;&#xA;Far more concerning is network propagation effects between large and&#xA;&gt; small miners.&#xA;&#xA;&#xA;On a related note, the Bitcoin-NG paper took a big step towards moving&#xA;these kinds of concerns out of the realm of gut-feelings and wavy hands&#xA;into science. In particular, it introduced metrics for fairness (i.e.&#xA;differential&#xA;rate in orphans experienced by small and large miners), hash power&#xA;efficiency, as well as consensus delay.&#xA;&#xA;&#xA;&gt; For that class of issues, if you are in an environemnt&#xA;&gt; where selfish mining is possible - a fairly flat, easily DoS/sybil&#xA;&gt; attacked network topology - the profitability difference between small&#xA;&gt; and large miners even *without* attacks going on is a hugely worrying&#xA;&gt; problem.&#xA;&#xA;&#xA;Indeed, there is a slight, quantifiable benefit to larger pools. Which is&#xA;why&#xA;we need to be diligent about not letting pools get too big.&#xA;&#xA;&#xA;&gt; Note though that Eligius is *not* the only pool to have had problems&#xA;&gt;&#xA;with block withholding, though AFAIK Eligius is the only one who has&#xA;&gt; gone on record so far. (as I said in my original post, I&#39;m relaying&#xA;&gt; information given to me under condition of confidentiality)&#xA;&gt;&#xA;&#xA;I can see why they don&#39;t want to go public with this: it means that they&#xA;are less profitable than other pools.&#xA;&#xA;It still looks to me like Ittay&#39;s discovery is doing exactly the right&#xA;thing:&#xA;this pool will need to be more careful when signing up new people,&#xA;curbing its otherwise steady march towards the 51% boundary.&#xA;&#xA;- egs&#xA;&#xA;&#xA;- egs&#xA;-------------- next part --------------&#xA;An HTML attachment was scrubbed...&#xA;URL: &lt;http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20151228/2e490a2b/attachment.html&gt;</html></oembed>