Wallet¶
We will setup a wallet to hold the accounts. As simplification we use the same mnemonic for both roles. In a real program you would choose one mnemonic per role.
Note
A mnemonic is an alternative representation of an Ethereum secret key.
HD Wallet¶
Setting up the wallet consists of parsing the mnemonic, deriving a wallet from it and deriving accounts from that wallet. To structure our program, we introduce a setupWallet function that will do these three steps. Thanks to miguelmota’s mnemonic parser it looks like this:
func setupWallet(role Role) (*perunhd.Account, *perunhd.Wallet, error) {
rootWallet, err := hdwallet.NewFromMnemonic(cfg.mnemonic)
if err != nil {
return nil, nil, fmt.Errorf("creating hd wallet: %w", err)
}
// Alice has account index 0 and Bob 1.
wallet, err := perunhd.NewWallet(rootWallet, "m/44'/60'/0'/0/0", uint(role))
if err != nil {
return nil, nil, fmt.Errorf("deriving path: %w", err)
}
// Derive the first account from the wallet.
acc, err := wallet.NewAccount()
if err != nil {
return nil, nil, fmt.Errorf("deriving hd account: %w", err)
}
return acc, wallet, nil
}
We pass the role to the function since we need to create one account for each role. The third argument to NewWallet defines the index of the first account that will be later on created with NewAccount. Alice will have the first account (index 0) and Bob the second (index 1). The “m/44’/60’/0’/0/0” argument defines the derivation path. We just use the default value here.
Note
These accounts will be used throughout the code to sign on- and off-chain transactions. You could create multiple accounts to keep on- and off-chain accounts separate.
Note
HD Transactor¶
Signing transactions is quite a complex thing in Ethereum. go-perun abstracts most of it away but we still have to deal with the remnants. Ethereum has multiple (currently three) different transaction signature algorithms. go-perun exposes this functionality to the user but in our case, it is enough to use the EIP155 signature algorithm and 1337 as chain id. We will need this Transactor in the next step:
func createTransactor(wallet *perunhd.Wallet) *perunhd.Transactor {
// 1337 is the default chain id for ganache-cli.
signer := types.NewEIP155Signer(big.NewInt(1337))
return perunhd.NewTransactor(wallet.Wallet(), signer)
}
Note