<oembed><type>rich</type><version>1.0</version><author_name>npub1j3u42vq63qzs2nyddgkf4s4t7pa85x855vas54e6yauxsvpf2wcsacwg9h</author_name><author_url>https://nostr.ae/npub1j3u42vq63qzs2nyddgkf4s4t7pa85x855vas54e6yauxsvpf2wcsacwg9h</author_url><provider_name>njump</provider_name><provider_url>https://nostr.ae</provider_url><html>📅 Original date posted:2016-12-11&#xA;📝 Original message:Andrew Johnson wrote:&#xA;&gt; &#34;You miss something obvious that makes this attack actually free of cost.&#xA;&gt; Nothing will &#34;cost them more in transaction fees&#34;. A miner can create&#xA;&gt; thousands of transactions paying to himself, and not broadcast them to&#xA;&gt; the network, but hold them and include them in the blocks he mines. The&#xA;&gt; fees are collected by him because transactions are included in a block&#xA;&gt; that he mined and the left amount is in another wallet of the same&#xA;&gt; person. Repeat this continuously to fill blocks.&#34;&#xA;&gt; &#xA;&gt; This is easily detectable as long as the network isn&#39;t heavily&#xA;&gt; partitioned(which is an assumption we make today in order for&#xA;&gt; transaction propagation to work reliably as well as for xThin and&#xA;&gt; CompactBlocks to work effectively to reduce block transmission time). &#xA;&gt; Other miners would have an incentive to intentionally orphan blocks that&#xA;&gt; contained a large number of transactions that their nodes were unaware of.&#xA;&gt; &#xA;&gt; I don&#39;t think this sort of attack would last long.  Even later when&#xA;&gt; subsidies are drastically reduced, you would still lose out on&#xA;&gt; significant genuine fee revenue if your orphan rate increased even&#xA;&gt; 10%(one out of ten of your poison blocks intentionally orphaned by&#xA;&gt; another miner).&#xA;&gt; &#xA;&#xA;I disagree.&#xA;&#xA;I didn&#39;t say this is impossible to detect, but it is hard to act against&#xA;it. One miner orphaning the block intentionally is very unlikely if that&#xA;miner acts rationally. It would only make sense if 51% of the hash rate&#xA;would intentionally orphan it. Otherwise the miner who intentionally&#xA;orphans a valid block, let&#39;s say block X, has to continue to mine one in&#xA;its place on top of block X-1, and by the time he finds one:&#xA;&#xA;a) his block X&#39; is rejected by other miners because they already have a&#xA;valid block X on top of which they already started to mine;&#xA;&#xA;b) block X+1 was already found and broadcasted, so the miner who&#xA;orphaned X intentionally is on the shorter chain ignored by the network.&#xA;&#xA;So, one miner cannot do anything about it. Even a pool cannot do&#xA;anything about it, because the loss is greater. You need 51% of the hash&#xA;rate to intentionally orphan it, and all the miners forming 51% need to&#xA;be colluding and know for sure that every one will intentionally orphan&#xA;the said block, otherwise there&#39;s a huge risk of loss for who does it.&#xA;Nobody would gamble to do this (I am not sure if gambling is the right&#xA;word, since the loss is 100% sure here). But, we are not discussing 51%&#xA;attacks because those are a different topic.&#xA;&#xA;-------------- next part --------------&#xA;A non-text attachment was scrubbed...&#xA;Name: signature.asc&#xA;Type: application/pgp-signature&#xA;Size: 488 bytes&#xA;Desc: OpenPGP digital signature&#xA;URL: &lt;http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20161212/952907bb/attachment.sig&gt;</html></oembed>