<oembed><type>rich</type><version>1.0</version><author_name>npub1wu8nl4rek0s38jw0p5tx4h8a0vu75f33v5ucc0ndj2fza5yav05q36fwsk</author_name><author_url>https://nostr.ae/npub1wu8nl4rek0s38jw0p5tx4h8a0vu75f33v5ucc0ndj2fza5yav05q36fwsk</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 11:30 AM, Emin Gün Sirer &lt;&#xA;bitcoin-dev at lists.linuxfoundation.org&gt; wrote:&#xA;&#xA;&gt;&#xA;&gt;&#xA;&gt; On Mon, Dec 28, 2015 at 2:12 PM, Peter Todd via bitcoin-dev &lt;&#xA;&gt; bitcoin-dev at lists.linuxfoundation.org&gt; wrote:&#xA;&gt;&#xA;&gt;&gt; Do you specifically mean selfish mining as defined in Emin Gün&#xA;&gt;&gt; Sirer/Ittay Eyal&#39;s paper? Keep in mind that attack is only a significant&#xA;&gt;&gt; issue in a scenario - one malicious miner with &gt;30% hashing power -&#xA;&gt;&gt; where you&#39;re already very close to the margins anyway; the difference&#xA;&gt;&gt; between a 50% attack threshold and a 30% attack threshold isn&#39;t very&#xA;&gt;&gt; significant.&#xA;&gt;&gt;&#xA;&gt;&#xA;&gt; This is not quite right: we know that selfish mining is a guaranteed win&#xA;&gt; at 34%. We do not know when exactly it begins to pay off. The more&#xA;&gt; consolidated and centralized the other mining pools, the less of a threat&#xA;&gt; it is below 34%; the more decentralized, the more likely it is to pay off&#xA;&gt; at lower thresholds.&#xA;&gt;&#xA;&#xA;Exactly.&#xA;&#xA;&#xA;&gt; Far more concerning is network propagation effects between large and&#xA;&gt;&gt; small miners.&#xA;&gt;&#xA;&gt;&#xA;&gt; On a related note, the Bitcoin-NG paper took a big step towards moving&#xA;&gt; these kinds of concerns out of the realm of gut-feelings and wavy hands&#xA;&gt; into science. In particular, it introduced metrics for fairness (i.e.&#xA;&gt; differential&#xA;&gt; rate in orphans experienced by small and large miners), hash power&#xA;&gt; efficiency, as well as consensus delay.&#xA;&gt;&#xA;&gt;&#xA;&gt;&gt; For that class of issues, if you are in an environemnt&#xA;&gt;&gt; where selfish mining is possible - a fairly flat, easily DoS/sybil&#xA;&gt;&gt; attacked network topology - the profitability difference between small&#xA;&gt;&gt; and large miners even *without* attacks going on is a hugely worrying&#xA;&gt;&gt; problem.&#xA;&gt;&#xA;&gt;&#xA;&gt; Indeed, there is a slight, quantifiable benefit to larger pools. Which is&#xA;&gt; why&#xA;&gt; we need to be diligent about not letting pools get too big.&#xA;&gt;&#xA;&gt;&#xA;&gt;&gt; Note though that Eligius is *not* the only pool to have had problems&#xA;&gt;&gt;&#xA;&gt; with block withholding, though AFAIK Eligius is the only one who has&#xA;&gt;&gt; gone on record so far. (as I said in my original post, I&#39;m relaying&#xA;&gt;&gt; information given to me under condition of confidentiality)&#xA;&gt;&gt;&#xA;&gt;&#xA;&gt; I can see why they don&#39;t want to go public with this: it means that they&#xA;&gt; are less profitable than other pools.&#xA;&gt;&#xA;&#xA;This I disagree with -- if they know that they have been attacked, then&#xA;there is every reason to come forward with this information.&#xA;&#xA;First of all, it offers an explanation for poor profits (this is better&#xA;than unexplained poor profits).&#xA;&#xA;Second of all, if one pool can be attacked then any pool can be attacked --&#xA;this is not a reason not to mine on a particular pool.  If anything, it&#39;s a&#xA;reason to diversify hashrate among many pools.&#xA;&#xA;--Adam&#xA;-------------- next part --------------&#xA;An HTML attachment was scrubbed...&#xA;URL: &lt;http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20151228/8c25dd48/attachment-0001.html&gt;</html></oembed>