NDWallet Core

A WebAssembly-based core library for cryptographic operations in browser environments. This library provides high-performance cryptographic primitives for key derivation, encryption/decryption, secret sharing, and seed phrase management.

Features

• WebAuthn Integration: Seamless integration with the WebAuthn API for passkey-based authentication
• PRF Extension Support: Use the WebAuthn PRF extension for more secure key derivation
• Key Derivation: Derive cryptographic keys from WebAuthn responses
• Encryption/Decryption: AES-GCM encryption for secure data storage
• Secret Sharing: Shamir's Secret Sharing for distributing secrets across multiple locations
• Seed Phrase Management: BIP39 seed phrase generation, validation, and conversion
• Wallet Module: High-level wallet creation and management functions
• WASM Performance: Near-native performance for cryptographic operations

Installation

npm install ndwallet-core

Prerequisites

To build this library, you'll need:

1. Rust and Cargo (https://rustup.rs/)
2. wasm-pack (https://rustwasm.github.io/wasm-pack/installer/)
3. Node.js and npm

Building

# Build the WASM module and TypeScript wrapper
npm run build

Usage

Core Cryptographic Functions

import { ndWalletCore, LOCAL_SHARE_ENCRYPTION_CONTEXT } from 'ndwallet-core';

// Start WebAuthn registration with PRF extension
async function register() {
  // Get registration options from your server
  let options = await fetchRegistrationOptionsFromServer();
  
  // Add PRF extension to options
  options = ndWalletCore.addPrfExtensionToRegistrationOptions(options);
  
  // Start WebAuthn registration
  const response = await ndWalletCore.startRegistration(options);
  
  // Derive a master key from the PRF output
  const masterKey = ndWalletCore.deriveMasterKeyFromPrf(response);
  
  // Derive an encryption key for a specific context
  const encryptionKey = ndWalletCore.deriveEncryptionKey(masterKey, LOCAL_SHARE_ENCRYPTION_CONTEXT);
  
  // Generate a seed phrase
  const seedPhrase = ndWalletCore.generateSeedPhrase();
  
  // Split the seed phrase into shares (2 of 3 threshold)
  const shares = ndWalletCore.splitSecret(seedPhrase, 2, 3);
  
  // Encrypt a share
  const encryptedShare = ndWalletCore.encryptData(shares[0], encryptionKey);
  
  // Send the registration response and other data to your server
  await sendToServer(response, encryptedShare);
}

// Start WebAuthn authentication with PRF extension
async function authenticate() {
  // Get authentication options from your server
  let options = await fetchAuthenticationOptionsFromServer();
  
  // Get the PRF salt from your server
  const prfSalt = await getPrfSaltFromServer();
  
  // Add PRF extension to options
  options = ndWalletCore.addPrfExtensionToAuthenticationOptions(options, prfSalt);
  
  // Start WebAuthn authentication
  const response = await ndWalletCore.startAuthentication(options);
  
  // Derive a master key from the PRF output
  const masterKey = ndWalletCore.deriveMasterKeyFromPrf(response);
  
  // Derive an encryption key for a specific context
  const encryptionKey = ndWalletCore.deriveEncryptionKey(masterKey, LOCAL_SHARE_ENCRYPTION_CONTEXT);
  
  // Get encrypted share from localStorage or server
  const encryptedShare = getEncryptedShare();
  
  // Decrypt the share
  const share = ndWalletCore.decryptData(encryptedShare, encryptionKey);
  
  // Send the authentication response to your server
  await sendToServer(response);
}

### Wallet Module

```javascript
import {
  generateSeedPhrase,
  createWallet,
  restoreFromBackup,
  getAddress,
  recoverSeedPhrase
} from 'ndwallet-core';

// Generate a new seed phrase
const seedPhrase = generateSeedPhrase();

// Create a wallet
const wallet = await createWallet({
  seedPhrase,
  network: 'ethereum',
  accountIndex: 0,
  storage: {
    storeLocally: true,
    storeOnServer: true,
    createBackup: true
  }
});

console.log('Wallet address:', wallet.address);

// Get address for different network/account
const btcAddress = getAddress(wallet, 'bitcoin', 0);

See the Wallet Module README for more details.

API Reference

Constants

• LOCAL_SHARE_ENCRYPTION_CONTEXT: Context for local share encryption
• SERVER_SHARE_ENCRYPTION_CONTEXT: Context for server share encryption
• BACKUP_SHARE_ENCRYPTION_CONTEXT: Context for backup share encryption

WebAuthn API

• startRegistration(options): Start WebAuthn registration with PRF extension
• startAuthentication(options): Start WebAuthn authentication with PRF extension
• addPrfExtensionToRegistrationOptions(options, prfSalt): Add PRF extension to registration options
• addPrfExtensionToAuthenticationOptions(options, prfSalt): Add PRF extension to authentication options
• generate_prf_salt(): Generate a random PRF salt
• create_prf_extension(salt): Create a PRF extension input for WebAuthn
• extract_prf_from_response(response): Extract PRF output from WebAuthn response

Key Derivation

• deriveMasterKeyFromPrf(response): Derive a master key from a WebAuthn response using PRF extension
• derive_encryption_key(masterKey, context): Derive an encryption key from a master key and context
• deriveEncryptionKey(masterKey, context): High-level wrapper for derive_encryption_key

Encryption/Decryption

• encrypt_data(data, key): Encrypt data using AES-GCM
• encryptData(data, key): High-level wrapper for encrypt_data
• decrypt_data(encryptedData, key): Decrypt data using AES-GCM
• decryptData(encryptedData, key): High-level wrapper for decrypt_data

Seed Phrase Management

• generate_seed_phrase(): Generate a random BIP39 seed phrase
• generateSeedPhrase(): High-level wrapper for generate_seed_phrase
• seed_phrase_to_seed(seedPhrase): Convert a BIP39 seed phrase to a seed
• seedPhraseToSeed(seedPhrase): High-level wrapper for seed_phrase_to_seed

Secret Sharing

• split_secret(secret, threshold, shares): Split a secret into shares using Shamir's Secret Sharing
• splitSecret(secret, threshold, shares): High-level wrapper for split_secret
• combine_shares(shares): Combine shares to reconstruct a secret
• combineShares(shares): High-level wrapper for combine_shares

License

MIT