Overview

This library enables Internet Computer canisters to sign transactions for EVM-compatible blockchains.

This is a two-part process:

Create new addresses on the Internet Computer using distributed ECDSA key generation
Sign transactions with these addresses as the canister itself or in behalve of the canister users using threshold ECDSA signatures

There an example project at ic-evm-sign-starter.

Features

Create EVM addresses
Sign EVM transactions
Manages transaction nonce
Supports different chain ids
Takes care of various tx types

Supported Tx Types: Legacy, EIP1559, EIP2930

Getting Started

Starter Project

You can get start quickly with ic-evm-sign-starter.

Existing Project

1. Install the library

Run cargo add ic-evm-sign in your project

2. Create new EVM address

Create a new EVM-compatible address from a canister

use ic_evm_sign;

#[update]
async fn create_address() -> Result<String, String> {

    let principal_id = ic_cdk::caller();
    let response = ic_evm::create_address(principal_id).await
        .map_err(|e| format!("Failed to create address {}", e))
        .unwrap();

    Ok(response.address)
}

Test locally with:

dfx canister call ${canister_name} create_address

3. Sign EVM transaction

Sign an EVM-compatible transaction from a canister

use ic_evm_sign;

#[update]
async fn sign_tx(hex_raw_tx: Vec<u8>) -> Result<String, String> {

    let chain_id = 1;
    let principal_id = ic_cdk::caller();
    let response = ic_evm_sign::sign_transaction(hex_raw_tx, chain_id, principal_id).await
        .map_err(|e| format!("Failed to sign transaction {}", e))
        .unwrap();

    Ok(response.sign_tx)
}

Test it locally with:

dfx canister call ${canister_name} sign_tx '(vec {${hex_raw_tx}}: vec nat8)'

Example:

dfx canister call ${canister_name} sign_tx '(vec {236; 128; 133; 5; 66; 135; 40; 189; 130; 117; 48; 148; 112; 153; 121; 112; 197; 24; 18; 220; 58; 1; 12; 125; 1; 181; 14; 13; 23; 220; 121; 200; 136; 13; 224; 182; 179; 167; 100; 0; 0; 0; 128; 128; 128}: vec nat8)'

For transaction hex:

0xec808505428728bd8275309470997970c51812dc3a010c7d01b50e0d17dc79c8880de0b6b3a764000000808080

How it works

New Address

Receive principal from the canister
Creates a new ECDSA public key on IC
Calculates the EVM address from the public key
Saves the new address to the canister state based on principal

Transaction Signing

Receive a raw transaction, chain id and a principal from the canister
Gets principal's public key from the canister state
Prepares "message" to sign from raw transaction and chain id
Signs "message" to sign and gets transaction signature
Calculates recovery id from "message" to sign, signature and public key
And then gets the signed transaction from raw transaction, chain id and recovery id
Stores the transaction to the canister state based on principal

How to's & guides

Different EVMs

Use a different EVM-compatible blockchain using chain_id in:

ic_evm_sign::sign(hex_raw_tx, chain_id, principal_id)

Find chain ids at: https://chainlist.org

Transaction types

You can sign different transaction types hex by passing their corresponding hex using hex_raw_tx in:

ic_evm_sign::sign(hex_raw_tx, chain_id, principal_id)

Find transaction types at: https://github.com/ethereum/execution-specs

Contributing

Get started

Download the repo with git clone
Run unit tests with cargo test

To develop on the local frontend:

Start a hardhat node with npm start in dev/local-node (terminal 1) - Requires npm i
Run an ic replica with dfx start (terminal 2)
And deploy the example canister with dfx deploy
Then start the example frontend with npm start (terminal 3) in dev/frontend - Requires npm i

ic-evm-sign 0.0.2