@picocash/sdk

Wallet-lite for agents (architecture component 5). Stateless-capable: the SDK holds no tokens — every method takes proofs and returns proofs, and storage is the caller's problem (a file, a DB row, a KV entry).

import { Wallet, verifyProofOffline } from '@picocash/sdk';

const wallet = new Wallet({ mintUrl: 'http://localhost:3338' });
const quote = await wallet.requestMintQuote(1_000_000);        // → pay quote.deposit on Tempo
// … transferWithMemo(deposit.to, amount, deposit.memo) …
const proofs = await wallet.mintProofs(quote.quote_id, 1_000_000); // DLEQ-verified, carries r

const { bundle, change } = await wallet.send(proofs, 250_000); // exact bundle + change
const claimed = await wallet.receive(bundle);                  // offline-verify, then own via swap
await wallet.meltProofs('0x…', claimed);                       // back to on-chain funds

Key properties:

• Every minted/swapped proof carries dleq: {e, s, r}, so anyone can verify it offline against the mint's published keys (verifyProofOffline) — the basis of agent-to-agent transfer and MPP accept-then-settle.
• Every signature from the mint is DLEQ-verified before the SDK trusts it; a mint that can't prove its signatures throws.
• serializeToken / parseToken implement PIP-06 picoA… tokens; wallet.send() returns the string, wallet.receive() accepts it.
• wallet.createLink(token) / wallet.receive(link) implement PIP-07 token links: AES-GCM client-side, key in the URL fragment, burn-after-read at the relay.
• pcBindSecretHex / parsePcBindSecret implement the canonical PC-BIND challenge-bound secrets from PIP-05.
• Mint errors surface as MintApiError with the mint's machine-readable code and recovery hint.

Tests run against an in-process mint (no HTTP, no chain): npm test.

Locked tokens (PIP-08 P2PK)

import { p2pkPublicKey } from '@picocash/crypto';

// human: fund an agent that can spend only with merchant M; reclaim after 24h if unused
const { token, change } = await wallet.sendLocked(proofs, 500_000, merchantPubkey, {
  locktime: Math.floor(Date.now() / 1000) + 86_400,
  refund: [p2pkPublicKey(myKey)],
});

// merchant: claim (signs with its key and swaps to unconditional proofs)
const mine = await merchantWallet.receive(token, { unlockKey: merchantKey });

// anyone: inspect the lock offline
lockOf(proof); // { data: '02…', locktime, refund: […], … } | null