<oembed><type>rich</type><version>1.0</version><author_name>npub1ej6vep7y2km5l6awukffelg8yeppkth2vjkjk9jypd5w336rxggs3p9cq8</author_name><author_url>https://nostr.ae/npub1ej6vep7y2km5l6awukffelg8yeppkth2vjkjk9jypd5w336rxggs3p9cq8</author_url><provider_name>njump</provider_name><provider_url>https://nostr.ae</provider_url><html>📅 Original date posted:2017-04-05&#xA;📝 Original message:#bitcoin at freenode:&#xA; 00:04    gmaxwell| lol poon pretending that he isn&#39;t complicit in all this stuff.&#xA;&#xA;Are you *fucking* serious? Is this how you resolve all problems? I&#39;m&#xA;taking you seriously and having second thoughts and want to make public&#xA;commitments to do the right thing without any evidence and you come out&#xA;and say *this*?&#xA;&#xA;On Thu, Apr 06, 2017 at 12:17:17AM +0000, Gregory Maxwell via bitcoin-dev wrote:&#xA;&gt; On Wed, Apr 5, 2017 at 11:05 PM, theymos via bitcoin-dev&#xA;&gt; &lt;bitcoin-dev at lists.linuxfoundation.org&gt; wrote:&#xA;&gt; &gt; This seems to be a serious security problem.  Would it be possible to have&#xA;&gt; &gt; a flag-day softfork included in Bitcoin Core as soon as 0.14.1? I think that a trigger&#xA;&gt; &gt; 3-6 months from release should be sufficient for enough of the economy to upgrade,&#xA;&gt; &gt; given the severity of the issue.&#xA;&gt; &#xA;&gt; Not 0.14.1 because that is in RC already and will hopefully be out in a week.&#xA;&gt; &#xA;&gt; I think the speed of adoption depends a lot of the level of support&#xA;&gt; from the community. I don&#39;t believe there are any technical hurdles to&#xA;&gt; implementing this relatively quickly (and I specifically propose using&#xA;&gt; the users choice of the segwit commitment or a modified form in order&#xA;&gt; to lower the technical complexity and risk).&#xA;&gt; &#xA;&gt; &gt; BIP 141 says that the the commitment is optional if there are no SegWit transactions in&#xA;&gt; &gt; the block,  so will today&#39;s SegWit-ready miners always produce it even when optional&#xA;&gt; &gt; according to BIP 141, as required by this softfork?&#xA;&gt; &#xA;&gt; This is the default behavior as of 0.13.2, but I haven&#39;t gone out to&#xA;&gt; measure this which is why the backwards compatibility section of the&#xA;&gt; BIP isn&#39;t written yet.&#xA;&gt; &#xA;&gt; &#xA;&gt; While I&#39;m posting, I&#39;ve had a dozen off-list emails that presented me&#xA;&gt; with some FAQ:&#xA;&gt; &#xA;&gt; Many people asked what other protocol upgrades beyond segwit could run&#xA;&gt; into the same incompatibility.&#xA;&gt; &#xA;&gt; Many proposed improvements to Bitcoin require additional&#xA;&gt; transaction-dependent commitment data.&#xA;&gt; &#xA;&gt; Examples include:&#xA;&gt; &#xA;&gt; (1) Segwit.&#xA;&gt; (2) UTXO commitments. (non-delayed, at least)&#xA;&gt; (3) Committed Bloom filters&#xA;&gt; (4) Committed address indexes&#xA;&gt; (5) STXO commitments (non-delayed).&#xA;&gt; (6) Weak blocks&#xA;&gt; (7) Most kinds of fraud proofs&#xA;&gt; -- to state a few.&#xA;&gt; &#xA;&gt; Unfortunately, putting *any* commitment to data dependent on the right&#xA;&gt; hand side of the hash tree in the left hand side (e.g. coinbase) means&#xA;&gt; a massive increase in the computation required for covert boosting,&#xA;&gt; because it means you can&#39;t use the left+right side combinations to&#xA;&gt; eliminate most of the hashing.&#xA;&gt; &#xA;&gt; It&#39;s plausible, in fact, that this extra computation could completely&#xA;&gt; nullify the ASICBOOST advantage-- though this depends a lot on the&#xA;&gt; fine details of the implementation.&#xA;&gt; &#xA;&gt; This proposal does not itself propose nullifying ASICBOOST entirely,&#xA;&gt; it proposes severely handicapping the covert form of it, and&#xA;&gt; eliminating the differential advantage for boosting miners related to&#xA;&gt; the use of transaction-dependent commitments.&#xA;&gt; &#xA;&gt; Basically there are two completely separate concerns: that boosting&#xA;&gt; can produce a monopoly advantage which could be severely harmful to&#xA;&gt; the ecosystem, and that the efficient implementation of _covert_&#xA;&gt; boosting can severely harm many useful protocol improvements.   My&#xA;&gt; proposal only addresses the second concern, by (I believe) completely&#xA;&gt; leveling the playing field so that opposing commitments will not break&#xA;&gt; boosting any worse, and by making covert boosting less appealing in&#xA;&gt; general.&#xA;&gt; &#xA;&gt; Use of the segwit-style commitment even in non-segwit blocks is sufficient&#xA;&gt; because the segwit commitment commits to all  transactions  (except&#xA;&gt; the coinbase) and not just segwit ones.&#xA;&gt; (It was designed this way so that lite clients that needed witness&#xA;&gt; data could work with just one tree).&#xA;&gt; _______________________________________________&#xA;&gt; bitcoin-dev mailing list&#xA;&gt; bitcoin-dev at lists.linuxfoundation.org&#xA;&gt; https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev&#xA;&#xA;-- &#xA;Joseph Poon</html></oembed>