<oembed><type>rich</type><version>1.0</version><title>Delcin wrote</title><author_name>Delcin (npub14x…wd3w5)</author_name><author_url>https://yabu.me/npub14xz8l0zxkmqsjug3ahhpyddyy8ahp99rm30degnyzrc7qntmnu7srwd3w5</author_url><provider_name>njump</provider_name><provider_url>https://yabu.me</provider_url><html>Amazing thing about bitcoin that we take for granted is that it allows Alice to send sats to Bob while Bob is offline.&#xA;&#xA;We need L2/L3 protocols on top of bitcoin to avoid high fee rates.&#xA;Cashu ecash is what I would consider an L3 protocols which allows Alice to send ecash with Bob, which a trusted mint acts as a bank.&#xA;But this requires Bob to be online! Tradeoffs!!&#xA;NOTE: Whoever the first to redeem the ecash token from the mint gets paid! So it has to be kept as secret between Alice and Bob, just like paper cash.&#xA;&#xA;In internet we would like things to work asynchronously. That is even when Bob is offline, he must be able to receive ecash from Alice.&#xA;&#xA;Cashu NUT-11 addresses this problem by facilitating the creation of ecash tokens which are locked to a public key, very similar to how bitcoin UTXOs are locked in Transaction output.&#xA;&#xA;NIP-61 defines the format in which these payments can be stored in a nostr-relay. Bob has to publish his cashu pubkey, mints he trust etc., as a nutzap info event and Alice can publish the ecash tokens which are locked into Bob&#39;s public key as nutzapp payment event.&#xA;&#xA;I have written a code example in rust using nostr_sdk and cdk https://github.com/delcin-raj/nip61-example-rs</html></oembed>