hyperwave-wallet-cashu

A Chaumian ecash (Cashu) implementation of the hyperwave-wallet interface — self-custodial bitcoin on a Lightning-connected mint, unit sat. This is the desktop default wallet for hyperwave-engine.

• Participation fees are burned as ecash P2PK-locked to a NUMS ("nothing-up-my-sleeve") pubkey — the unspendable black-hole analog — tagged with the seat memo (NUT-11). Verifiable as spent via NUT-07 (verifyBurnTx).
• Tips are bearer tokens the recipient redeems (send → receive).
• Any Lightning Cashu peer interoperates regardless of mint (type is the generic 'cashu').

Cashu is stateful — proofs are bearer funds held locally (ProofStore), so this wallet persists proofs outside the engine's ephemeral store.

Install

npm install hyperwave-wallet-cashu

Use

A host injects the factory into the engine:

const { createEngine } = require('hyperwave-engine');
const { createCashuWallet } = require('hyperwave-wallet-cashu');

const engine = createEngine({
  storageDir: '/tmp/hyperwave/a',
  config: { topicId: 'my-topic:v1', walletOptions: { mint: DEFAULT_MINT } },
  deps: { createPayments: createCashuWallet }
});

The dev default mint is the free auto-paying testnut mint (https://testnut.cashu.space) — no real funds; call wallet.fund(sats) and it's paid automatically. A real mint returns a bolt11 invoice to pay.

Exports

• createCashuWallet(options) / CashuWallet — the Wallet implementation. Beyond the base interface it adds fund(amountSats, { onInvoice }), receive(token) (redeem a tip), and consolidate({ sourceMint }) (sweep proofs into one mint).
• CASHU_WALLET_TYPE ('cashu'), CASHU_UNIT ('sat'), DEFAULT_MINT.
• verifyBurnProofs, burnTags, p2pkLockPubkey, MEMO_TAG_KEY (cashu-burn — pure structural burn verification).
• numsBurnPubkey, NUMS_DOMAIN (nums — the deterministic on-curve burn pubkey).
• ProofStore, MAX_HISTORY (per-mint ecash proof store).
• installBareWebShims (fetch/WebCrypto shims so cashu-ts runs under Bare).

See docs/cashu.md in the repo for the full money model.

Runtime

CommonJS; runs under Bare (the shims bridge cashu-ts's web APIs) and Node.

Testnet only

Ecash on a testnet Lightning mint; no real value. Do not point it at a production mint with real funds.

License: Apache-2.0