Cashu

Protocolo P2P

A free and open-source Chaumian ecash protocol built for Bitcoin, enabling private, instant, and offline-capable digital payments. The protocol defines an ecash system with two parties — a mint (server that issues and redeems ecash tokens) and a wallet (client that holds bearer tokens). Blind signatures preserve privacy: a mint cannot link token issuance to redemption, providing strong untraceability. Multiple independent wallet and mint implementations exist across Python, TypeScript, Rust, and other languages. Transactions are instant and final. Transfers between mints are routed via the Lightning Network. Protocol specifications are published as NUTs (Notation, Usage, and Terminology). Governed by the OpenCash Association.

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Detalles

Licencia Open source (MIT); https://github.com/cashubtc
Estado de Desarrollo 🟢 Activo
Detalle del Estado de Desarrollo Released (multiple production wallet and mint implementations; iOS/Android apps; PWA; CLI tools; Python nutshell reference; TypeScript cashu-ts; Rust CDK)
Propietario OpenCash Association (protocol stewardship); cashubtc GitHub org (open-source implementations); community-developed
Órgano de Gobierno OpenCash Association (protocol stewardship via the NUTs specification process)
País Global / Cypherpunk community
Año de Inicio 2022
Stack Rust (CDK — Cashu Development Kit); TypeScript (cashu-ts); Python (nutshell reference implementation); protocol-agnostic (any language can implement NUTs)
Financiamiento Community / Donations (OpenCash Association; cypherpunk community; no VC funding identified)
Última Investigación 1 jul 2026

Dominios de Caso de Uso

Evolución de Plataformas y Soberanía

Protocolo P2P Atributos

Orígenes Cypherpunk / Privacy payments (based on David Wagner's 1996 variant of Chaumian blinding; motivated by need for private, peer-to-peer digital cash that preserves user privacy from mints and third parties; Bitcoin-native)
Base de Datos Mint-local (each mint maintains its own token database; no global ledger; bearer token model means wallet holds tokens locally; no user account database at mint)
Lenguaje de Consulta N/A (payment protocol; no query language)
Formatos de Datos Cashu NUT tokens (JSON-encoded blind signature tokens); Lightning Network invoices (for mint-to-mint transfers and Bitcoin on/off-ramp); BOLT11 (Lightning invoice format)
Edición Colaborativa en Vivo N/A
Edición de Texto Enriquecido N/A
Soporte Móvil Yes (iOS and Android wallet apps — multiple implementations)
Soporte Web Yes (PWA web wallet implementations)
Aplicaciones Nativas Yes (CLI tools; desktop wallet implementations)
Términos Free / Open source (protocol is free; mints may charge fees; OpenCash Association accepts donations)
Fondos Undisclosed
Basado En Bitcoin (Layer 1 — token backing and settlement); Lightning Network (inter-mint transfers and Bitcoin on/off-ramp); Chaumian blind signatures (David Wagner 1996 variant); RSA/Ed25519 blind signature schemes
Arquitectura P2P Mint-and-wallet federation (mints issue and redeem tokens; wallets hold bearer tokens locally; peer-to-peer token transfers between wallets without mint involvement; blind signatures prevent mint from linking issuance to redemption; offline-capable token transfers between wallets)
Red de Superposición Application-wide (scoped to individual mint deployments; cross-mint via Lightning routing; no global DHT or relay network required)
Direccionamiento por Contenido No (token model; no content addressing)
Local-First Yes (bearer tokens stored locally on wallet device; offline token transfers between wallets possible without internet; Lightning required only for mint interactions)
Cifrado de Extremo a Extremo (E2EE) Yes (blind signatures provide strong untraceability; mint cannot link user identity to transactions; no user accounts at mint; no transaction graph visible to mint)
Biblioteca de CRDTs N/A (payment protocol; no collaborative editing)
Tolerancia a Fallos Bizantinos N/A (payment protocol; Byzantine fault tolerance not applicable)
Firma Blind signatures (RSA or Ed25519 blind signature scheme; mint signs tokens without seeing token identity; wallet holds and presents tokens)
Permisos Open (any wallet can interact with any compliant mint; no permissioning beyond Lightning Network access)
Compatibilidad con la Web Semántica No (payment protocol; no semantic web features)
Contrato Inteligente No (not a smart contract platform; conditional payment logic not in base protocol)
Posición en la Pila del Protocolo Application layer (sits above Bitcoin/Lightning transport; defines token issuance, transfer, and redemption semantics; not a transport protocol)
Incorporación de Activos/Valor Native (ecash tokens are the value-bearing primitive; asset embedding is the protocol's core purpose)
Madurez del Protocolo / Estandarización Released / Community standard (multiple independent production implementations across 5+ languages; active ecosystem of wallets and mints; NUTs specification published; OpenCash Association stewardship; no formal IETF or ISO standardization; de facto standard for Bitcoin ecash)