ethereumjs-util

What is ethereumjs-util?

The ethereumjs-util package provides a set of utility functions for Ethereum. These utilities include functions for handling addresses, big numbers, hashing, and encoding/decoding data according to the Ethereum protocol standards. It is a foundational package that can be used to develop Ethereum-based applications, facilitating tasks such as transaction formatting, signature verification, and data conversion.

What are ethereumjs-util's main functionalities?

Address Formatting

Converts an Ethereum address to its checksummed version to prevent case sensitivity errors.

const { toChecksumAddress } = require('ethereumjs-util');
const checksumAddress = toChecksumAddress('0xfb6916095ca1df60bb79ce92ce3ea74c37c5d359');
console.log(checksumAddress);

Hashing

Generates a keccak256 hash of the input data, a common hashing function used in Ethereum.

const { keccak256 } = require('ethereumjs-util');
const hash = keccak256(Buffer.from('hello'));
console.log('Hash:', hash.toString('hex'));

Signature Verification

Signs a message hash with a private key and serializes the signature in a format compatible with RPC calls.

const { ecsign, toRpcSig } = require('ethereumjs-util');
const privateKey = Buffer.from('c87509a1c067bbde7aebb4d3c0a0b8ab8bd02b676c91662b5f41c4ec9863d8ee', 'hex');
const msgHash = keccak256(Buffer.from('hello'));
const sig = ecsign(msgHash, privateKey);
const serializedSig = toRpcSig(sig.v, sig.r, sig.s);
console.log('Signature:', serializedSig);

Other packages similar to ethereumjs-util

web3

Web3 is a comprehensive Ethereum library that includes utilities similar to ethereumjs-util but also provides a wide range of functionalities to interact with Ethereum nodes directly. It covers the entire Ethereum API and is more extensive for building DApps.

ethers

Ethers is a lightweight library that aims to be a complete and compact library for interacting with the Ethereum Blockchain and its ecosystem. It includes utilities for addresses, big numbers, and hashing, similar to ethereumjs-util, but also features a complete set of functions to interact with smart contracts and blockchain data.

README

SYNOPSIS

A collection of utility functions for Ethereum. It can be used in Node.js and in the browser with browserify.

INSTALL

npm install ethereumjs-util

USAGE

import assert from 'assert'
import { isValidChecksumAddress, unpadBuffer, BN } from 'ethereumjs-util'

const address = '0x2F015C60E0be116B1f0CD534704Db9c92118FB6A'
assert.ok(isValidChecksumAddress(address))

assert.equal(unpadBuffer(Buffer.from('000000006600', 'hex')), Buffer.from('6600', 'hex'))

assert.equal(new BN('dead', 16).add(new BN('101010', 2)), 57047)

API

Documentation

Modules

• account
  • Account class
  • Private/public key and address-related functionality (creation, validation, conversion)
• address
  • Address class and type
• bytes
  • Byte-related helper and conversion functions
• constants
  • Exposed constants
    • e.g. KECCAK256_NULL_S for string representation of Keccak-256 hash of null
• hash
  • Hash functions
• object
  • Helper function for creating a binary object (DEPRECATED)
• signature
  • Signing, signature validation, conversion, recovery
• types
  • Helpful TypeScript types
• externals
  • Helper methods from ethjs-util
  • Re-exports of BN, rlp

ethjs-util methods

The following methods are available provided by ethjs-util:

• arrayContainsArray
• toBuffer
• getBinarySize
• stripHexPrefix
• isHexPrefixed
• isHexString
• padToEven
• intToHex
• fromAscii
• fromUtf8
• toUtf8
• toAscii
• getKeys

They can be imported by name:

import { intToHex, stripHexPrefix } from 'ethereumjs-util'

Re-Exports

Additionally ethereumjs-util re-exports a few commonly-used libraries. These include:

• BN.js (version 5.x)
• rlp (version 2.x)

EthereumJS

See our organizational documentation for an introduction to EthereumJS as well as information on current standards and best practices.

If you want to join for work or do improvements on the libraries have a look at our contribution guidelines.

LICENSE

MPL-2.0