@shroud-fi/payments

Sender-side stealth payment construction for ShroudFi. ETH + ERC-20 on Base.

npm i @shroud-fi/payments viem

What it does

@shroud-fi/payments is the sender side of a ShroudFi payment. For each transfer it:

1. Derives a fresh one-time stealth address from the recipient's (spendPub, scanPub) meta-address.
2. Computes the EIP-5564 announcement and broadcasts it on-chain.
3. Sends ETH or ERC-20 to that one-time address.
4. Resolves recipient meta-addresses from a plain EVM wallet via the on-chain ERC-6538 registry.

The graph of who-pays-whom never reaches the public ledger — every payment lands at an unlinkable destination only the recipient can spend from.

Quick start

import { sendETHPayment, lookupMetaAddress } from '@shroud-fi/payments';
import { createTransport } from '@shroud-fi/transport';

const transport = createTransport({ chain: 'base', rpcUrl });
const meta = await lookupMetaAddress(transport, '0xRecipientWallet');

await sendETHPayment({
  transport,
  walletClient,
  recipientMeta: meta.metaAddressEncoded,
  amountWei: 10_000_000_000_000n, // 0.00001 ETH
});

Exports

| Symbol | Purpose | |---|---| | sendETHPayment(args) | Derive stealth, announce, transfer ETH — one call. | | sendERC20Payment(args) | Same shape for ERC-20. USDC on Base mainnet is the v1 target. | | sweepETH · sweepERC20 | Direct sweep from stealth address to destination. Fee-free, no relayer. | | lookupMetaAddress(transport, wallet) | Resolve a wallet's registered meta-address via ERC-6538. | | RecipientNotOnboardedError | Thrown when a wallet has no published meta-address. Structured .wallet field for privacy-safe UX. |

Full API reference: shroudfi.live/sdk#payments

Threat model notes

• Amounts are visible. v1 ShroudFi provides recipient unlinkability, not amount privacy. Amount-fingerprinting is an active mitigation surface.
• Address rotation is mandatory. Sweeping detected payments back to a long-lived wallet collapses the privacy property — use one-shot destinations or batched sweeps.

License

MIT — see LICENSE.

Part of the ShroudFi privacy SDK for AI agents on Base.