0.1.1 • Public • Published


A lightweight wallet implementation. At the moment it supports key creation and conversion between various formats.

Motivations are:

  • be lightweight
  • work in a browser
  • use a single, maintained version of crypto library (and that should be in line with newchainjs-util and newchainjs-tx)
  • support import/export between various wallet formats
  • support BIP32 HD keys

Features not supported:

  • signing transactions
  • managing storage (neither in node.js or the browser)

Wallet API


  • generate([icap]) - create an instance based on a new random key (setting icap to true will generate an address suitable for the ICAP Direct mode)
  • generateVanityAddress(pattern) - create an instance where the address is valid against the supplied pattern (this will be very slow)
  • fromPrivateKey(input) - create an instance based on a raw private key
  • fromExtendedPrivateKey(input) - create an instance based on a BIP32 extended private key (xprv)
  • fromPublicKey(input, [nonStrict]) - create an instance based on a public key (certain methods will not be available)
  • fromExtendedPublicKey(input) - create an instance based on a BIP32 extended public key (xpub)
  • fromV1(input, password) - import a wallet (Version 1 of the Ethereum wallet format)
  • fromV3(input, password, [nonStrict]) - import a wallet (Version 3 of the Ethereum wallet format). Set nonStrict true to accept files with mixed-caps.
  • fromEthSale(input, password) - import an Ethereum Pre Sale wallet

For the V1, V3 and EthSale formats the input is a JSON serialized string. All these formats require a password.

Note: fromPublicKey() only accepts uncompressed Ethereum-style public keys, unless the nonStrict flag is set to true.

Instance methods:

  • getPrivateKey() - return the private key
  • getPublicKey() - return the public key
  • getAddress() - return the address
  • getChecksumAddressString() - return the address with checksum
  • getV3Filename([timestamp]) - return the suggested filename for V3 keystores
  • toV3(password, [options]) - return the wallet as a JSON string (Version 3 of the Ethereum wallet format)

All of the above instance methods return a Buffer or JSON. Use the String suffixed versions for a string output, such as getPrivateKeyString().

Note: getPublicKey() only returns uncompressed Ethereum-style public keys.

Thirdparty API

Importing various third party wallets is possible through the thirdparty submodule:

var thirdparty = require('newchainjs-wallet/thirdparty')


  • fromEtherCamp(passphrase) - import a brain wallet used by Ether.Camp
  • fromEtherWallet(input, password) - import a wallet generated by EtherWallet
  • fromKryptoKit(seed) - import a wallet from a KryptoKit seed
  • fromQuorumWallet(passphrase, userid) - import a brain wallet used by Quorum Wallet

HD Wallet API

To use BIP32 HD wallets, first include the hdkey submodule:

var hdkey = require('newchainjs-wallet/hdkey')


  • fromMasterSeed(seed) - create an instance based on a seed
  • fromExtendedKey(key) - create an instance based on a BIP32 extended private or public key

For the seed we suggest to use bip39 to create one from a BIP39 mnemonic.

Instance methods:

  • privateExtendedKey() - return a BIP32 extended private key (xprv)
  • publicExtendedKey() - return a BIP32 extended public key (xpub)
  • derivePath(path) - derive a node based on a path (e.g. m/44'/0'/0/1)
  • deriveChild(index) - derive a node based on a child index
  • getWallet() - return a Wallet instance as seen above

Provider Engine

The Wallet can be easily plugged into provider-engine to provide signing:

const WalletSubprovider = require('newchainjs-wallet/provider-engine')

<engine>.addProvider(new WalletSubprovider(<wallet instance>))

Note it only supports the basic wallet. With a HD Wallet, call getWallet() first.

Remarks about toV3

The options is an optional object hash, where all the serialization parameters can be fine tuned:

  • uuid - UUID. One is randomly generated.
  • salt - Random salt for the kdf. Size must match the requirements of the KDF (key derivation function). Random number generated via crypto.getRandomBytes if nothing is supplied.
  • iv - Initialization vector for the cipher. Size must match the requirements of the cipher. Random number generated via crypto.getRandomBytes if nothing is supplied.
  • kdf - The key derivation function, see below.
  • dklen - Derived key length. For certain cipher settings, this must match the block sizes of those.
  • cipher - The cipher to use. Names must match those of supported by OpenSSL, e.g. aes-128-ctr or aes-128-cbc.

Depending on the kdf selected, the following options are available too.

For pbkdf2:

  • c - Number of iterations. Defaults to 262144.
  • prf - The only supported (and default) value is hmac-sha256. So no point changing it.

For scrypt:

  • n - Iteration count. Defaults to 262144.
  • r - Block size for the underlying hash. Defaults to 8.
  • p - Parallelization factor. Defaults to 1.

The following settings are favoured by the Go Ethereum implementation and we default to the same:

  • kdf: scrypt
  • dklen: 32
  • n: 262144
  • r: 8
  • p: 1
  • cipher: aes-128-ctr


MIT License

Copyright (C) 2016 Alex Beregszaszi



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