Eth

A simple library to build and sign Ethereum transactions. Allows separataion of key and node management. Sign transactions and handle keys anywhere you can run ruby, boradcast transactions through any node.

Installation

Add this line to your application's Gemfile:

gem 'eth'

And then execute:

$ bundle

Or install it yourself as:

$ gem install eth

Usage

Keys

Create a new public/private key and get its address:

key = Eth::Key.new
key.private_hex
key.public_hex
key.address # EIP55 checksummed address

Import an existing key:

old_key = Eth::Key.new priv: private_key

Or decrypt an encrypted key:

decrypted_key = Eth::Key.decrypt File.read('./some/path.json'), 'p455w0rD'

You can also encrypt your keys for use with other ethereum libraries:

encrypted_key_info = Eth::Key.encrypt key, 'p455w0rD'

Transactions

Build a transaction from scratch:

tx = Eth::Tx.new({
  data: hex_data,
  gas_limit: 21_000,
  gas_price: 3_141_592,
  nonce: 1,
  to: key2.address,
  value: 1_000_000_000_000,
})

Or decode an encoded raw transaction:

tx = Eth::Tx.decode hex

Then sign the transaction:

tx.sign key

Get the raw transaction with tx.hex, and broadcast it through any Ethereum node. Or, just get the TXID with tx.hash.

Utils

Validate an EIP55 checksummed address:

Eth::Utils.valid_address? address

Or add a checksum to an existing address:

Eth::Utils.format_address "0x4bc787699093f11316e819b5692be04a712c4e69" # => "0x4bc787699093f11316e819B5692be04A712C4E69"

HD Vaults

This branch adds HD wallet functionality which can be seeded with Trezor style mnemonic words.

# Create a new vault
v = Eth::Vault.new
key = v.get_key(1) 

# Restore a vault from a mnemonic
v = Eth::Vault.new(secret_seed_phrase: "trouble mesh impact indoor inquiry aim index deposit weekend alter pottery chef eye page elder awesome paper sport arch illegal muscle another blossom arctic")
key = v.get_key(2)

# Specify an HD Root Path (see: https://github.com/ethereum/EIPs/issues/84)

v = Eth::Vault.new({secret_seed_phrase: "trouble mesh impact indoor inquiry aim index deposit weekend alter pottery chef eye page elder awesome paper sport arch illegal muscle another blossom arctic"}, "m/44'/60'/0'/0/0")
key = v.get_key

web3.eth.sign functionality

You can sign arbitrary messages which can be verified on the EVM using ecrecover.

v = Eth::Vault.new
signer = Eth::RpcSigner.new(v.get_key)
a = signer.sign_message('foobar')

Configure

In order to prevent replay attacks, you must specify which Ethereum chain your transactions are created for. See EIP 155 for more detail.

Eth.configure do |config|
  config.chain_id = 1 # nil by default, meaning valid on any chain
end

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/se3000/ethereum-tx. Tests are encouraged.

Tests

First install the Ethereum common tests:

git submodule update --init

Then run the associated tests:

rspec

License

The gem is available as open source under the terms of the MIT License.

TODO

Better test suite.
Expose API for HD keys.
Support signing with libsecp256k1.

digix-eth

Development

Runtime

Eth