ECVRF

A production-grade TypeScript implementation of Elliptic Curve Verifiable Random Function (ECVRF) using secp256k1, following RFC 9381 for suite ECVRF-SECP256k1-SHA256-TAI.

About

This library provides a robust implementation of the ECVRF (Verifiable Random Function) using the secp256k1 elliptic curve. The implementation is based on cryptographic standards and designed for production use.

Features

• Standards-compliant ECVRF implementation following RFC 9381
• Support for secp256k1 curve
• Deterministic outputs for the same inputs
• Robust error handling
• Comprehensive test coverage
• Well-documented API
• Suitable for production use

Installation

# Using npm
npm install @simplevrf/ecvrf

# Using yarn
yarn add @simplevrf/ecvrf

# Using bun
bun add @simplevrf/ecvrf

Usage

Basic Example

import { 
  generateVRFKeyPair, 
  proveVRF, 
  verifyVRF, 
  vrfProofToHash,
  hexToBytes,
  bytesToHex,
  utf8ToBytes 
} from 'ecvrf';

// Generate a key pair
const { sk, pk } = generateVRFKeyPair();
console.log('Private key:', sk);
console.log('Public key:', pk);

// Create a message (can be any data)
const message = 'My message to prove';
const messageBytes = utf8ToBytes(message);
const messageHex = bytesToHex(messageBytes);

// Generate a proof
const { proofHex, gammaHex } = proveVRF(sk, messageHex);
console.log('Proof:', proofHex);

// Verify the proof
const isValid = verifyVRF(pk, messageHex, {
  p1: proofHex.slice(0, 66),  // First 32 bytes
  p2: proofHex.slice(66, 130), // Next 32 bytes
  p3: proofHex.slice(130, 194), // Next 32 bytes
  p4: parseInt(proofHex.slice(194), 16) // Last byte
});
console.log('Verification result:', isValid); // Should be true

// Convert the proof to a deterministic hash
const hash = vrfProofToHash(proofHex);
console.log('VRF output hash:', hash);

API Reference

generateVRFKeyPair(): { sk: string; pk: string }

Generates a new ECVRF key pair.

• Returns: An object containing:
  • sk: Private key as a hex string
  • pk: Public key as a hex string

proveVRF(privateKeyHex: string, alphaHex: string): { proofHex: string; gammaHex: string }

Generates an ECVRF proof for a message using a private key.

• Parameters:
  • privateKeyHex: Private key as a hex string
  • alphaHex: Message as a hex string
• Returns: An object containing:
  • proofHex: The ECVRF proof as a hex string
  • gammaHex: The gamma point of the proof as a hex string

verifyVRF(publicKeyHex: string, alphaHex: string, chunkedProof: ChunkedProof): boolean

Verifies an ECVRF proof.

• Parameters:
  • publicKeyHex: Public key as a hex string
  • alphaHex: Original message as a hex string
  • chunkedProof: The ECVRF proof split into chunks
• Returns: A boolean indicating if the proof is valid

vrfProofToHash(proofHex: string): string

Converts an ECVRF proof to a deterministic hash.

• Parameters:
  • proofHex: The ECVRF proof as a hex string
• Returns: A hex string containing the hash

Utility Functions

• hexToBytes(hex: string): Uint8Array: Converts a hex string to bytes
• bytesToHex(bytes: Uint8Array): string: Converts bytes to a hex string
• utf8ToBytes(str: string): Uint8Array: Converts a UTF-8 string to bytes
• concatHex(...hexes: string[]): string: Concatenates hex strings
• padHex(hex: string, length: number): string: Pads a hex string to a specified length
• concatBytes(...arrays: Uint8Array[]): Uint8Array: Concatenates byte arrays

Use Cases

• Random beacon
• Provably fair games and lotteries
• Unpredictable but verifiable selections
• Proof of resource ownership
• Cryptographic sortition
• Leader election in distributed systems

Development

Prerequisites

• Node.js >= 16
• npm, yarn, or bun

Setup

# Clone the repository
git clone https://github.com/darthbenro008/simplevrf.git
cd packages/ecvrf

# Install dependencies
npm install

Build

npm run build

Running Tests

# Run all tests
npm test

# Run tests in watch mode
npm run test:watch

# Generate test vectors and run vector tests
npm run test:vectors

# Run test coverage
npm run test:coverage

Security

This library has been designed for production use, but as with any cryptographic library:

• Properly secure your private keys
• Keep dependencies up to date
• Review any changes to the code before deploying to production
• Consider a security audit for critical applications

License

Copyright 2025 Hemanth Krishna Licensed under MIT License : https://opensource.org/licenses/MIT