ledger-eth-lib

This is a WIP. Consider it alpha

This is a library to interact with ledger-app-eth, the Ethereum app for the Ledger hardware wallets. It's goal is to make interfacing with the Ledger nice and simple with well known Ethereum+Python tools.

NOTE: Tested to work on Ledger Nano S and Nano X. Will probalby work with Ledger Blue

WARNING: The Ledger apps have changed the way accounts are derived with the release of Ledger Live. If you created your Ledger account(s) with the older Chrome app and want to use those account(s) with this library, you will need to set the LEDGER_LEGACY_ACCOUNTS env var. You can only use one or the other at a time. See the notes in source for more information.

Environment Configuration

There are a couple of environment variables that can affect the behavior of ledger-eth-lib, documented below:

• MAX_ACCOUNTS_FETCH[default: 5]: The maximum accounts that will be fetched when looking up by address. If you created more than 5 accounts on your Ledger device, you may want to adjust this.
• LEDGER_LEGACY_ACCOUNTS: If set (to anything), ledger-eth-lib will use the legacy Ledger bip32 derivation that was used to create accounts before Ledger Live.

CLI Usage

python -m ledgereth [command]

Get Accounts

To get the available accounts from your Ledger:

python -m ledgereth accounts

Web3.py Integration

ledger-eth-lib provides a Web3.py middleware. It will automatically intercept the relevant JSON-RPC calls and respond with data from your Ledger device.

from web3.auto import w3
from ledgereth.web3 import LedgerSignerMiddleware
w3.middleware_onion.add(LedgerSignerMiddleware)

Intercepted JSON-RPC methods:

• eth_sendTransaction
• eth_accounts

Quickstart

Get Accounts

Fetch the availible accounts.

from ledgereth import get_accounts
accounts = get_accounts()
my_account = accounts[0].address

Create and Sign a Transaction

Create a transaction object and sign it with the default account.

from ledgereth import create_transaction
tx = create_transaction(
    '0xb78f53524ae9d465279e7c3495f71d5db2419e13',  # to
    '0x4dae53ee778a324bd317bd270d6227406b6bd4ec',  # from
    int(1e18),  # value
    int(1e5),  # gas limit
    int(1e9),  # gas price
    1,  # nonce
)
signature = '0x{}{}{}'.format(
    hex(tx.v)[2:],
    hex(tx.r)[2:],
    hex(tx.s)[2:],
)

Sign an Existing Transaction Object

Sign a Transaction object from pyethereum(or similar RLP serializable):

from ledgereth import sign_transaction
tx = sign_transaction(tx)
signature = '0x{}{}{}'.format(
    hex(tx.v)[2:],
    hex(tx.r)[2:],
    hex(tx.s)[2:],
)

TODO

• Add fake dongle support to pytest suite so tests can be run without a real Ledger and human interaction
• Fill out tests
• Add messaging signing support