@ocash/sdk

TypeScript ZKP SDK for privacy-preserving token operations — deposit, transfer, and withdraw via UTXO model and zk-SNARK proofs.

Documentation | 中文文档

Features

• Zero-Knowledge Proofs — Groth16 zk-SNARK via Go WASM for on-chain privacy
• UTXO Model — Poseidon2 commitments, Merkle trees, nullifiers
• Multi-Environment — Browser, Node.js, Electron/Tauri
• Modular — Factory pattern with event-driven modules, compose what you need
• 4 Storage Adapters — Memory, IndexedDB, File, KV

Install

pnpm add @ocash/sdk

Quick Start

import { createSdk, SEPOLIA_TESTNET } from '@ocash/sdk';

const sdk = createSdk({
  chains: [SEPOLIA_TESTNET],
  onEvent: console.log,
});

await sdk.core.ready();
await sdk.wallet.open({ seed: 'your-secret-seed-phrase' });
await sdk.sync.syncOnce();

const balance = await sdk.wallet.getBalance({
  chainId: SEPOLIA_TESTNET.chainId,
  assetId: SEPOLIA_TESTNET.tokens![0]!.id,
});

Pre-configured chain presets exported from @ocash/sdk:

Preset	Chain	Chain ID
ETH_MAINNET	Ethereum	1
BSC_MAINNET	BNB Chain	56
BASE_MAINNET	Base	8453
SEPOLIA_TESTNET	Sepolia	11155111
BSC_TESTNET	BSC Testnet	97

Also available: MAINNET_CHAINS and TESTNET_CHAINS arrays.

Entry Points

Import	Environment	Extra
@ocash/sdk	Universal	MemoryStore
@ocash/sdk/browser	Browser	+ IndexedDbStore
@ocash/sdk/node	Node.js	+ FileStore

SDK Modules

sdk.core      — WASM & circuit initialization
sdk.keys      — BabyJubjub key derivation
sdk.crypto    — Commitments, nullifiers, memo encryption
sdk.assets    — Chain / token / relayer configuration
sdk.storage   — Persistence adapter
sdk.wallet    — Session, UTXOs, balance
sdk.sync      — Memo / nullifier / Merkle sync
sdk.merkle    — Merkle proofs & membership witnesses
sdk.planner   — Coin selection, fee estimation
sdk.zkp       — zk-SNARK proof generation
sdk.tx        — Relayer request builder
sdk.ops       — End-to-end orchestration

Operations

Transfer

const keyPair = sdk.keys.deriveKeyPair(seed);
const prepared = await sdk.ops.prepareTransfer({
  chainId,
  assetId,
  amount,
  to: recipientAddress,
  ownerKeyPair: keyPair,
  publicClient,
});
const result = await sdk.ops.submitRelayerRequest({ prepared, publicClient });
const txHash = await result.waitRelayerTxHash;

Withdraw

const prepared = await sdk.ops.prepareWithdraw({
  chainId,
  assetId,
  amount,
  recipient: evmAddress,
  ownerKeyPair: keyPair,
  publicClient,
});
const result = await sdk.ops.submitRelayerRequest({ prepared, publicClient });

Deposit

const ownerPub = sdk.keys.getPublicKeyBySeed(seed);
const prepared = await sdk.ops.prepareDeposit({
  chainId,
  assetId,
  amount,
  ownerPublicKey: ownerPub,
  account: walletAddress,
  publicClient,
});
if (prepared.approveNeeded) {
  await walletClient.writeContract(prepared.approveRequest);
}
await walletClient.writeContract(prepared.depositRequest);

Lifecycle

createSdk(config)            →  Initialize
sdk.core.ready()             →  Load WASM & circuits
sdk.wallet.open({ seed })    →  Derive keys, open storage
sdk.sync.start()             →  Background sync (or syncOnce)
sdk.ops.prepareTransfer()    →  Plan, prove, build request
sdk.wallet.close()           →  Release keys, flush storage

Requirements

• Node.js >= 20.19.0
• Browser: WebAssembly + crypto.getRandomValues + fetch

Development

pnpm install
pnpm run build
pnpm run test          # Run tests
pnpm run dev           # Browser demo
pnpm run demo:node     # Node.js demo
pnpm run docs:dev      # Documentation dev server

License

MIT