<oembed><type>rich</type><version>1.0</version><author_name>npub1g6vxlp4e0nyhs2dqxxcryztyf5f5hyuaq93nw4r87zcnv0sdsa0qqsl5wd</author_name><author_url>https://nostr.ae/npub1g6vxlp4e0nyhs2dqxxcryztyf5f5hyuaq93nw4r87zcnv0sdsa0qqsl5wd</author_url><provider_name>njump</provider_name><provider_url>https://nostr.ae</provider_url><html>📅 Original date posted:2015-12-08&#xA;📝 Original message:On Tue, Dec 8, 2015 at 5:41 PM, Mark Friedenbach via bitcoin-dev &lt;&#xA;bitcoin-dev at lists.linuxfoundation.org&gt; wrote:&#xA;&#xA;&gt; A far better place than the generation transaction (which I assume means&#xA;&gt; coinbase transaction?) is the last transaction in the block. That allows&#xA;&gt; you to save, on average, half of the hashes in the Merkle tree.&#xA;&gt;&#xA;&#xA;This trick can be improved by only using certain tx counts.  If the number&#xA;of transactions is limited to a power of 2 (other than the extra&#xA;transactions), then you get a path of length zero.&#xA;&#xA;The number of non-zero bits in the tx count determings how many digests are&#xA;required.&#xA;&#xA;https://github.com/TierNolan/bips/blob/aux_header/bip-aux-header.mediawiki&#xA;&#xA;This gets the benefit of a soft-fork, while also keeping the proof lengths&#xA;small.  The linked bip has a 105 byte overhead for the path.&#xA;&#xA;The cost is that only certain transaction counts are allowed.  In the worst&#xA;case, 12.5% of transactions would have to be left in the memory pool.  This&#xA;means around 7% of transactions would be delayed until the next block.&#xA;&#xA;Blank transactions (or just transactions with low latency requirements)&#xA;could be used to increase the count so that it is raised to one of the&#xA;valid numbers.&#xA;&#xA;Managing the UTXO set to ensure that there is at least one output that pays&#xA;to OP_TRUE is also a hassle.&#xA;-------------- next part --------------&#xA;An HTML attachment was scrubbed...&#xA;URL: &lt;http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20151208/99821607/attachment.html&gt;</html></oembed>