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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Detalhes

Licença Open source (MIT); https://github.com/cashubtc
Status de Dev 🟢 Ativo
Detalhe do Status de Dev Released (multiple production wallet and mint implementations; iOS/Android apps; PWA; CLI tools; Python nutshell reference; TypeScript cashu-ts; Rust CDK)
Proprietário OpenCash Association (protocol stewardship); cashubtc GitHub org (open-source implementations); community-developed
Órgão de Governança OpenCash Association (protocol stewardship via the NUTs specification process)
País Global / Cypherpunk community
Ano de Início 2022
Stack Rust (CDK — Cashu Development Kit); TypeScript (cashu-ts); Python (nutshell reference implementation); protocol-agnostic (any language can implement NUTs)
Financiamento Community / Donations (OpenCash Association; cypherpunk community; no VC funding identified)
Última Investigação 1 de jul. de 2026

Domínios de Caso de Uso

Evolução de Plataformas e Soberania

Capacidades

Intercâmbio não monetário IA que preserva a privacidade

Protocolo P2P Atributos

Origens 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)
Banco de Dados 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)
Linguagem de Consulta N/A (payment protocol; no query language)
Formatos de Dados 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)
Edição Colaborativa em Tempo Real N/A
Edição de Texto Rico N/A
Suporte Móvel Yes (iOS and Android wallet apps — multiple implementations)
Suporte Web Yes (PWA web wallet implementations)
Aplicativos Nativos Yes (CLI tools; desktop wallet implementations)
Termos Free / Open source (protocol is free; mints may charge fees; OpenCash Association accepts donations)
Fundos Undisclosed
Baseado Em 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
Arquitetura 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)
Rede de Sobreposição Application-wide (scoped to individual mint deployments; cross-mint via Lightning routing; no global DHT or relay network required)
Endereçamento por Conteúdo 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)
Criptografia de Ponta a Ponta (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)
Tolerância a Falhas Bizantinas N/A (payment protocol; Byzantine fault tolerance not applicable)
Assinatura Blind signatures (RSA or Ed25519 blind signature scheme; mint signs tokens without seeing token identity; wallet holds and presents tokens)
Permissões Open (any wallet can interact with any compliant mint; no permissioning beyond Lightning Network access)
Compatibilidade com a Web Semântica No (payment protocol; no semantic web features)
Contrato Inteligente No (not a smart contract platform; conditional payment logic not in base protocol)
Posição na Pilha de Protocolo Application layer (sits above Bitcoin/Lightning transport; defines token issuance, transfer, and redemption semantics; not a transport protocol)
Incorporação de Ativo / Valor Native (ecash tokens are the value-bearing primitive; asset embedding is the protocol's core purpose)
Maturidade / Padronização do Protocolo 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)