Cashu Open-source Chaumian e-cash protocol for Bitcoin Lightning. Single mint operator (vs Fedimint's federated). Specs evolve via NUTs (github.com/cashubtc/nuts). Mint reference: (Python). Architecture - Mint : one entity issuing Cashu notes. - Wallet : holds notes, transacts. - Lightning bridge : mint accepts/sends LN payments. Lifecycle Mint (deposit BTC → notes) 1. Wallet asks mint for an LN invoice (specifying amount). 2. Wallet pays invoice via LN. 3. Mint signs blinded note(s) for the wallet (blind signing). 4. Wallet now holds notes, has anonymity within mint. Spend (intra-mint paymen…