Skip to main content

Smart Contract Wallet Usage

info

This section is limited to just for Web/JavaScript at the present moment

Smart Contract wallets like Argent are fully supported by the WalletConnect protocol.

However, there are some considerations to be taken when integrating WalletConnect in your dapp for Smart Contract wallets, regarding how the accounts are exposed in the session, message signatures are returned, and transactions are broadcasted.

Accounts​

tip

When you connect your dapp to a smart contract wallet, you will receive the smart account address for the wallet. This is not to be confused with the delegate keys that are used to sign messages and transactions.

You can detect smart contract wallets by verifying on-chain if the exposed account address has any associated code deployed.

import { providers, utils } from 'ethers'

const provider = new providers.JsonRpcProvider(rpcUrl)

const bytecode = await provider.getCode(address)

const isSmartContract = bytecode && utils.hexStripZeros(bytecode) !== '0x'

Smart contract wallets are essentially multi-signature wallets that use multiple keys to authorize operations on behalf of these smart contract accounts, so you will have to take into consideration how messages and transactions are handled by your dapp.

Messages​

Normally, when verifying signatures from "normal" accounts, which are Externally Owned Accounts (EOAs), you would use an ECDSA method called ecrecover() to retrieve the corresponding public key, which will then map to an address.

In the case of Smart Contract Wallets, you are not able to sign a message with the smart contract account. Therefore, the standard EIP-1271 was defined to outline a validation method which can be called on-chain, labeled isValidSignature().

contract ERC1271 {
  bytes4 constant internal MAGICVALUE = 0x1626ba7e;

  function isValidSignature(
    bytes32 _hash,
    bytes memory _signature
  )
    public
    view
    returns (bytes4 magicValue);
}

This method has a single parameter _hash which should be EIP-191 compliant and can be computed using:

import { utils } from 'ethers'

const hash = utils.hashMessage(message)

Transactions​

Smart Contract wallets, like Argent, commonly use the concept of meta transactions. These are a specific type of transaction that is signed by one or more key pairs but is submitted to the Ethereum network by a relayer.

The relayer pays the gas fee (in ETH), and the wallet will refund the relayer (in ETH or ERC20 tokens) up to an amount signed by the wallet's owner.

From your dapp's perspective, this is managed by the mobile wallet application. Your dapp will submit a regular { to, value, data } transaction to the web3 provider. This transaction will be transmitted to the mobile wallet application through WalletConnect.

The mobile wallet will transform the data into a meta transaction:

  • to will be the RelayerManager contract address
  • data will be the encoded data of the call to the execute() method with the relevant parameters

Your dapp will receive the transaction hash in order to monitor the status of the transaction, and events will be emitted as usual.

The relayer has the ability to replay a transaction with a higher gas price due to fluctuating network conditions. The transaction hash is modified, and the dapp will not be aware of the new transaction hash.

One solution could be for your dapp to observe a specific event being emitted instead of the transaction status. There is currently work on standardizing events for transactions replies that has been recently proposed via EIP-2831. We hope to improve our SDKs in the future to take this standard into account.