react-native-sapling

React Native bindings for madfish-sapling (Zcash Sapling crypto). Compatible with React Native 0.72.x.

All byte arrays are passed and returned as base64 strings in JavaScript.

Installation

npm install react-native-sapling
# or
yarn add react-native-sapling

Android

The library depends on madfish-sapling via JitPack. Ensure your root build.gradle has:

allprojects {
  repositories {
    maven { url 'https://jitpack.io' }
    // ...
  }
}

Then link the native module (React Native 0.72 usually auto-links):

npx react-native link react-native-sapling

iOS

1. Install pods: cd ios && pod install
2. Add the Madfish Sapling Swift package so the native code can use the Sapling library:
   • In Xcode, open your .xcworkspace
   • File → Add Package Dependencies…
   • Enter: https://github.com/madfish-solutions/madfish-sapling
   • Add the Sapling library to your app target (and ensure it is available to the RNSapling / react_native_sapling target if needed for linking)

Without this package, the iOS bridge still compiles but will return "Sapling package not linked" at runtime.

Usage

import * as Sapling from 'react-native-sapling';

// All arguments that are byte arrays are base64 strings; numeric values are numbers.

// Init parameters (spend + output params as base64)
await Sapling.initParameters(spendParamsBase64, outputParamsBase64);

// Proving context (create once, reuse for building a transaction)
const contextId = await Sapling.initProvingContext();
try {
  // ... use contextId in prepareOutputDescription, prepareSpendDescriptionWithSpendingKey, createBindingSignature
} finally {
  await Sapling.dropProvingContext(contextId);
}

// Keys (seed and derivation path; seed as base64)
const spendingKey = await Sapling.getExtendedSpendingKey(seedBase64, "m/32'/133'/0'");
const viewingKey = await Sapling.getExtendedFullViewingKey(seedBase64, "m/32'/133'/0'");
// Or from spending key:
const viewingKey2 = await Sapling.getExtendedFullViewingKeyFromSpendingKey(spendingKeyBase64);

// Payment address (viewing key + optional index as base64; omit index for default first address)
const address = await Sapling.getPaymentAddress(viewingKeyBase64, null);
const nextAddress = await Sapling.getNextPaymentAddress(viewingKeyBase64, indexBase64);

// Random scalar
const r = await Sapling.randR();

// … and the rest of the API: getProofAuthorizingKey, verifyCommitment, keyAgreement,
// merkleHash, computeNullifier, prepareOutputDescription, preparePartialOutputDescription,
// getRawPaymentAddress, getDiversifierFromRawPaymentAddress, getPkdFromRawPaymentAddress,
// createBindingSignature, prepareSpendDescriptionWithSpendingKey,
// prepareSpendDescriptionWithAuthorizingKey, signSpendDescription,
// getOutgoingViewingKey, getIncomingViewingKey

API (JS)

All methods return Promises. Byte arrays are base64 strings; numeric values are numbers.

| Method | Notes | |--------|--------| | initParameters(spendParamsBase64, outputParamsBase64) | Initialize Sapling parameters | | initProvingContext() | Returns contextId (number). Call dropProvingContext(contextId) when done. | | dropProvingContext(contextId) | Release proving context | | getProofAuthorizingKey(spendingKeyBase64) | | | verifyCommitment(commitment, address, value, rcm) | Returns boolean | | keyAgreement(pBase64, skBase64) | | | merkleHash(depth, lhsBase64, rhsBase64) | | | computeNullifier(viewingKey, address, value, rcm, position) | | | prepareOutputDescription(contextId, viewingKey, address, rcm, value) | | | preparePartialOutputDescription(contextId, address, rcm, esk, value) | | | getPaymentAddress(viewingKey, indexBase64 \| null) | indexBase64 null = first address | | getNextPaymentAddress(viewingKey, indexBase64) | | | getRawPaymentAddress(incomingViewingKey, diversifier) | | | getDiversifierFromRawPaymentAddress(address) | | | getPkdFromRawPaymentAddress(address) | | | randR() | Random scalar (base64) | | createBindingSignature(contextId, balance, sighashBase64) | | | prepareSpendDescriptionWithSpendingKey(contextId, spendingKey, address, rcm, ar, value, anchor, merklePath) | | | prepareSpendDescriptionWithAuthorizingKey(contextId, authorizingKey, address, rcm, ar, value, anchor, merklePath) | | | signSpendDescription(spendDescription, spendingKey, ar, sighash) | | | getExtendedSpendingKey(seedBase64, derivationPath) | | | getExtendedFullViewingKey(seedBase64, derivationPath) | | | getExtendedFullViewingKeyFromSpendingKey(spendingKeyBase64) | | | getOutgoingViewingKey(viewingKeyBase64) | | | getIncomingViewingKey(viewingKeyBase64) | |

License

ISC