2023-06-09T12:21:01Z https://yabu.me Konstantin Ketterer [ARCHIVE] https://yabu.me/npub1d38xn8fn3qsj4ruge6qces8qwljx993gkxkek8usmkrzllrn2d3q8v3l5r https://yabu.me/nevent1qqsxm2w0k4qsh3ymn7u3mzaye2lpq6y6vhjc024wdz9n76mzauwfq8szypkyu6vaxwyzz2503r8grrxqupm7gc5k9zc6mxcljrwcvtluwdfkyrdhhkv In reply to <a href='/nevent1qqsrnm77dqr0m7eqmpp5edcr368hcyyd3jdpgv2wlmrs0lxsyqk7nfchsvw56'>nevent1q…vw56</a><br/>_________________________<br/><br/>📅 Original date posted:2019-09-25<br/>📝 Original message:<br/>*Disclaimer*: I have just finished Highschool and I&#39;m only learning a bit<br/>in my free time.This may be fundamentally broken ;)<br/><br/>*Motivation*: If I had to timestamp multiple messages I could simply<br/>aggregate them in a merkle tree and pay relatively low fees per message.<br/>However, if I only need to timestamp something once in a while I need to<br/>rely on free services or pay high fees.<br/><br/>*Solution*: buy a place in a merkle tree &#34;risk-free&#34;<br/><br/>1. send hash x of my message (or the merkle root of another tree) to the<br/>timstamping server<br/>2. server calculates Pedersen commit: C = x*H + r*G, hashes it, builds<br/>merkle tree with other commits in it and publishes a valid transaction<br/>containing the merkle root to the Bitcoin blockchain<br/>3. after a certain number of block confirmations and with the given proof I<br/>can confirm that the commitment C is indeed part of the Bitcoin blockchain<br/>4. I now have to send a lightning payment with C - x*H = r*G as the payment<br/>point to the timestamping server and as a proof of payment the server must<br/>reveal r to receive the money.<br/><br/>--&gt; With both r and x I have a valid Pedersen commitment.<br/><br/>This introduces an additional security assumption to Bitcoin timestamps but<br/>if the discrete logarithm is broken Bitcoin has bigger problems than broken<br/>timestamps.<br/><br/>*Conclusion*<br/>This scheme essentially shifts the risk of a timestamping service from the<br/>buyer to the seller who now has to pay the onchain transaction fee upfront.<br/>Hence, the seller will most likely charge a small fee upfront just like<br/>some submarineswap providers do.<br/><br/>Regards<br/>Konstantin Ketterer<br/>-------------- next part --------------<br/>An HTML attachment was scrubbed...<br/>URL: &lt;<a href="http://lists.linuxfoundation.org/pipermail/lightning-dev/attachments/20190925/8d6502f0/attachment.html&gt">http://lists.linuxfoundation.org/pipermail/lightning-dev/attachments/20190925/8d6502f0/attachment.html&gt</a>; 2023-06-09T12:56:12Z