ethereumjs-wallet

ethereumjs-wallet

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

It is complemented by the following packages:

• ethereumjs-tx to sign transactions
• ethereumjs-icap to manipulate ICAP addresses
• store.js to use browser storage

Motivations are:

• be lightweight
• work in a browser
• use a single, maintained version of crypto library
• support import/export between various wallet formats

Features not supported:

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

API

Constructors:

• fromPrivateKey(input) - create an instance based on a raw key
• fromV1(input, password) - import a wallet (Version 1 of the Ethereum wallet format)
• fromV3(input, password) - import a wallet (Version 3 of the Ethereum wallet format)
• 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.

Instance methods:

• getPrivateKey() - return the private key
• getPublicKey() - return the public key
• getAddress() - return the address
• 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().

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