Installation

Install

npm install @opaquecash/opaque

Peer dependencies you typically also need:

Package	When
`viem`	Ethereum reads/writes, wallet clients
`@solana/web3.js`	Solana reads/writes (re-exported transitively)
`starknet`	Starknet reads/writes; wallet broadcast via `EthSigner` (starknet.js v10+)
`@opaquecash/react`	React apps: provider + hooks over the client (React hooks)
`@opaquecash/deployments`	Raw generated addresses/ABIs/program ids (Deployments)

WASM module

Scanning, sweeping, trait discovery, key reconstruction, and Groth16 witness generation run in a Rust→WASM module (opaque-scanner). Pass the JS glue URL as wasmModuleSpecifier:

await OpaqueClient.create({
  // ...
  wasmModuleSpecifier: "/pkg/cryptography.js",
});

Self-hosting (recommended for production)

Build from the scanner crate:

wasm-pack build --target web --out-dir pkg --out-name cryptography

Serve pkg/cryptography.js and pkg/cryptography_bg.wasm from your app’s public/ directory. The glue file loads the .wasm sibling automatically.

Do not hotlink https://www.opaque.cash/pkg/cryptography.js in production. Self-host the artifact so deploys are not blocked by CORS or third-party availability.

PSR admin without WASM

Schema and attestation management uses pure-JS DKSAP. You can omit wasmModuleSpecifier for issuer backends:

const issuer = await OpaqueClient.create({
  chainId: 11155111,
  rpcUrl,
  walletSignature,
  ethereumAddress,
  ethereumWalletClient,  // backend issuer
  // no wasmModuleSpecifier
});

await issuer.createSchema("ethereum", { /* … */ });

Calling scan, sweep, or generateReputationProof without WASM throws a clear error.

Signer matrix

Operation	Ethereum	Solana	Starknet
Reads (`getMySchemas`, `scan`, balances)	`rpcUrl`	`solana: { connection \| rpcUrl \| cluster }`	`starknet: {}`
Writes (`registerMetaAddress`, `sendStealthPayment`, PSR)	`ethereumProvider` or `ethereumWalletClient`	`solanaWallet: { publicKey, signTransaction }`	`build*` methods → app wallet
Scan / sweep / prove	`wasmModuleSpecifier`	`wasmModuleSpecifier` + `solana` config	`wasmModuleSpecifier` + `starknet: {}`

Starknet writes don’t go through the generic facade. sendStealthPayment and registerMetaAddress accept only ethereum and solana. On Starknet, buildStarknetStealthSend, buildStarknetSweep, and SNIP-12 on-behalf registration (via @opaquecash/stealth-chain-starknet) return unsigned calls your app’s Starknet wallet broadcasts — sweeps go out through a starknet.js EthSigner (v10+) and the stealth account self-funds its deploy fee. PSR schema/attestation issuance stays on Ethereum and Solana; Starknet does proof verification and gating only. Addresses come from getStarknetDeployment("sepolia") (packages @opaquecash/stealth-chain-starknet and @opaquecash/psr-chain-starknet). Starknet is at testnet-preview maturity — see the Starknet flow.

Backend issuer (Ethereum)

import { createWalletClient, http } from "viem";
import { privateKeyToAccount } from "viem/accounts";
import { sepolia } from "viem/chains";

const account = privateKeyToAccount(process.env.ISSUER_PRIVATE_KEY as `0x${string}`);
const walletClient = createWalletClient({ account, chain: sepolia, transport: http(rpcUrl) });

const client = await OpaqueClient.create({
  chainId: sepolia.id,
  rpcUrl,
  walletSignature: testEntropySignature,
  ethereumAddress: account.address,
  ethereumWalletClient: walletClient,
});

Backend issuer (Solana)

import { Keypair, Transaction } from "@solana/web3.js";

const keypair = Keypair.fromSecretKey(/* … */);

const client = await OpaqueClient.create({
  chainId: 11155111,  // EVM chainId required by config; unused on Solana-only path
  rpcUrl: "https://ethereum-sepolia.publicnode.com",
  walletSignature,
  ethereumAddress: "0x0000000000000000000000000000000000000001",
  solana: { rpcUrl: solanaRpc, cluster: "devnet" },
  solanaWallet: {
    publicKey: keypair.publicKey,
    signTransaction: async (tx: Transaction) => {
      tx.partialSign(keypair);
      return tx;
    },
  },
});

Monorepo / workspace

Link the local package during development:

{
  "dependencies": {
    "@opaquecash/opaque": "workspace:*"
  }
}

Build the SDK first: cd sdk && npm install && npm run build.

Runnable examples

sdk/examples/ ships one runnable script per flow:

Example	Flow
`from-wallet.ts`	Build a client from a unified signer (offline)
`scan.ts`	Unified cross-chain inbox scan + balances (read-only)
`send.ts`	Stealth send with optional delayed announcement (spends testnet ETH)
`psr-prove.ts`	Generate and verify a Groth16 reputation proof (offline)
`uab-readonly.ts`	Build a cross-chain announce request + read UAB inbox (read-only)

cd sdk && npm run build
npx tsx examples/from-wallet.ts

Get started

Concepts

Guides

SDK reference

Protocol

Install

WASM module

Self-hosting (recommended for production)

PSR admin without WASM

Signer matrix

Backend issuer (Ethereum)

Backend issuer (Solana)

Monorepo / workspace

Runnable examples

​Install

​WASM module

​Self-hosting (recommended for production)

​PSR admin without WASM

​Signer matrix

​Backend issuer (Ethereum)

​Backend issuer (Solana)

​Monorepo / workspace

​Runnable examples

Install

WASM module

Self-hosting (recommended for production)

PSR admin without WASM

Signer matrix

Backend issuer (Ethereum)

Backend issuer (Solana)

Monorepo / workspace

Runnable examples