ETH Transfer using KMS Signer

Here is an example of how one can use the eth kms signer, web3.py to perform ether transfer.

To install needed dependencies you can use:

pip install eth-kms-signer

Once you have an environment set up, import your required libraries:

from eth_kms_signer import EthKmsClient
from web3 import Web3

Instantiate the kms signer client

client = EthKmsClient(region_name=region_name)

Initialize a web3 instance with an Infura node

w3 = Web3(Web3.HTTPProvider(endpoint_uri=rpc_url))

Retrieve the address of the key id

from_address = client.get_address(key_id)

Find the current nonce from RPC using get_transaction_count method

nonce = w3.eth.get_transaction_count(from_address)

Create a transaction dictionary with the required parameters

tx = {
    "nonce": nonce,
    "to": "0x7EeD368F105a6eaC9Ac645bC3440fEa9A6C3D531",
    "value": w3.toWei(12, "wei"),
    "gas": 21000,
    "gasPrice": w3.toWei(1, "gwei"),
    "chainId": "0x4",
}

If you want the EIP 1559 dynamic fee transaction, omit the gasPrice and add maxFeePerGas, maxPriorityFeePerGas in the transaction dictionary.

tx = {
    "nonce": nonce,
    "to": "0x7EeD368F105a6eaC9Ac645bC3440fEa9A6C3D531",
    "value": w3.toWei(12, "wei"),
    "gas": 21000,
    "maxFeePerGas": w3.toWei(1, "gwei"),
    "maxPriorityFeePerGas": w3.toWei(1, "gwei"),
    "type": "0x2",
    "chainId": "0x4",
}

Create a signed transaction of the tx dictionary

signed_tx = client.sign_transaction(tx, key_id)

Broadcast the signed transaction using RPC's sendRawTransaction method

tx_hash = w3.eth.sendRawTransaction(signed_tx)

More detailed examples can be found in the project's example folder.