<oembed><type>rich</type><version>1.0</version><title>Federico Rivi wrote</title><author_name>Federico Rivi (npub1rd…0r3ys)</author_name><author_url>https://nostr.now/npub1rd0wwn037yltsh256d4urxjpsr6ye6dva6azaggsl848nwc64ehq60r3ys</author_url><provider_name>njump</provider_name><provider_url>https://nostr.now</provider_url><html>A proposal published on September 24 aims to transfer bitcoin while hiding amounts, recipients, and links between payments, without a soft fork and without changing Bitcoin&#39;s consensus rules.&#xA;&#xA;It&#39;s called Shielded Bitcoin. The authors are Clara Shikhelman, Mikhail Komarov, and Aleksei Moskvin of Alloc Init. The system borrows Zcash&#39;s structure, but reconstructs its own state from Bitcoin&#39;s history: a &#34;metaprotocol&#34; applied to data already published on the chain.&#xA;&#xA;Value circulates in the form of &#34;notes.&#34; A note contains satoshis and data that lets the recipient recognize and spend it.&#xA;&#xA;To prevent double-spending, each spent note produces a nullifier. This is a cryptographic marker published only once. If it reappears, the transaction is rejected. An observer sees the nullifier but cannot directly link it back to the note it derives from.&#xA;&#xA;Compared to CoinJoin, PayJoin, and Silent Payments, here even the amounts are meant to stay hidden.&#xA;&#xA;The project also separates spending keys from viewing keys. A reviewer can be given visibility into payments without handing over the funds. But a viewing key doesn&#39;t prove the balance, nor does it prove that the entire history has been shown.&#xA;&#xA;The hardest part remains: getting real bitcoin in and out of the private system. Alloc Init points to PIPEs v2 and witness encryption. A UTXO&#39;s key would only be recovered by presenting a valid proof; spending would then happen with a normal Schnorr signature.&#xA;nostr:naddr1qq3kvetjd4shgcfdxvcnsttkv4exjenfvdshyefdwdjku7np94mx2er9wfjsygqmtmn5mu0386u964xnd0qe5svq73xwnt8whgh2zy8eafumkx4wdcpsgqqqw4rswlkm05</html></oembed>