web3_universal_crypto

Cryptographic primitives for the Web3 Universal SDK. This package provides security-first implementations of Ed25519, Schnorr (BIP-340), and Secp256k1 for cross-chain signing.

Features

• 🔐 Ethereum Keystore V3: Full Scrypt (RFC 7914) & PBKDF2 support for encrypted JSON wallets.
• 🛡️ Zero Dependency: Pure Dart implementation of Scrypt, AES-128-CTR, and Keccak-256.
• 🧪 Strict Verification: Verified against official test vectors from NIST (AES/SHA), RFC (Scrypt/PBKDF2), and Ethereum Core.
• 🐚 Ed25519: High-performance implementation for Solana and Cosmos.
• 🔑 HD Wallet: Full BIP-32 and BIP-44 hierarchical deterministic derivation.

Installation

Add this to your pubspec.yaml:

dependencies:
  web3_universal_crypto: ^0.1.0

Quick Start

import 'package:web3_universal_crypto/web3_universal_crypto.dart';

void main() {
  // Generate a Schnorr signature
  final keyPair = SchnorrKeyPair.generate();
  final message = Uint8List.fromList([0x01, 0x02]);
  final signature = keyPair.sign(message);
  print('Signature: ${signature.toHex()}');
}

Platform Support

Android	iOS	Web	macOS	Windows	Linux
✅	✅	✅	✅	✅	✅

Usage Flow

sequenceDiagram
    participant M as Mnemonic
    participant S as Seed
    participant K as PrivateKey
    participant P as PublicKey
    M->>S: generateSeed(pass)
    S->>K: derive(path)
    K->>P: compute()
    P-->>U: Wallet Address

🏗️ Architecture

graph LR
    Entropy[Entropy Source] --> BIP39[BIP-39 Mnemonic]
    BIP39 --> Seed[PBKDF2 Seed]
    Seed --> HDMaster[BIP-32 Master Node]
    HDMaster --> Derived[BIP-44 Child Node]
    Derived --> ECDSA[secp256k1 KeyPair]
    
    style ECDSA fill:#bfb,stroke:#2d2,stroke-width:2px;

📚 Technical Reference

Core Classes

Class	Responsibility
Scrypt	RFC 7914 compliant KDF (N, r, p configurable).
KeystoreV3	Encrypts/Decrypts Ethereum JSON wallets (AES-128-CTR + MAC).
AES	AES-128 Block Cipher and CTR Stream Mode.
Bip39	Generates and validates mnemonic phrases and seeds.
HDWallet	Manages node trees and path-based key derivation.
EthKeyPair	Represents a raw private/public key pair and performs ECDSA.
Keccak	Provides Ethereum-standard Keccak-256 hashing.

🛡️ Security Considerations

• Memory Erasure: Use privateKey.fill(0) (if available in buffer context) after deriving keys to minimize resident memory risk.
• Entropy Source: Bip39.generate() uses Random.secure(). On some platforms, ensure the underlying system RNG is properly initialized.
• Do Not Log Keys: Never log or print private keys or mnemonics in production. Use obfuscated logging if necessary.

💻 Usage

Secure Multi-Account Derivation

import 'package:web3_universal_crypto/web3_universal_crypto.dart';

void main() {
  final mnemonic = "asset adjust total... (12 words)";
  final hdRoot = HDWallet.fromMnemonic(Mnemonic.fromSentence(mnemonic, WordList.english));

  // Derive Account #0 and Account #1
  final acc0 = hdRoot.derivePath("m/44'/60'/0'/0/0");
  final acc1 = hdRoot.derivePath("m/44'/60'/0'/0/1");

  print('Acc 0 Address: ${acc0.address}');
}

Keystore V3 (Encrypted Wallet)

import 'dart:convert';
import 'package:web3_universal_crypto/web3_universal_crypto.dart';

void main() {
  final password = "strong-password";
  final privateKey = Uint8List.fromList(List.generate(32, (i) => i));

  // Encrypt (produces standard V3 JSON)
  final keystore = KeystoreV3.encrypt(privateKey, password);
  print(jsonEncode(keystore));

  // Decrypt
  final recoveredKey = KeystoreV3.decrypt(keystore, password);
}

Performance Hashing

final hash = Keccak.hash(Uint8List.fromList([0x01, 0x02]));

📦 Installation

dependencies:
  web3_universal_crypto: ^0.2.0