Signing with a Mnemonic

The LocalSigner in the Chorus One SDK is a specialized implementation of the Signer interface that utilizes a BIP39 mnemonic for signing operations.

This signer is ideal for local environments where you need a straightforward and secure method to generate and manage cryptographic keys from mnemonic phrases.

Obtaining the Mnemonic and HD Path

Before initializing the LocalSigner you will need to prepare a BIP39 mnemonic and define the hierarchical deterministic (HD) path for key derivation.

Let's look at what these two key concepts are below:

• mnemonic: A string containing your BIP39 mnemonic phrase. This should be stored securely and kept private as it controls access to all addresses derived from it.

• hdPath: The BIP39 address derivation path, which is used to derive the specific key pair needed for signing. Commonly, this path follows the format m/44'/60'/0'/0/0 for Ethereum-compatible addresses.

• addressDerivationFn: A function that derives the address from the public key, implementing the AddressDerivationFn type and provided by Staker classes as static methods, e.g. SolanaStaker.getAddressDerivationFn, NearStaker.getAddressDerivationFn, etc.

type AddressDerivationFn = (publicKey: Uint8Array, hdPath: string) => Promise<Array<string>>

Address derivation processes across different blockchains typically involve a combination of elliptic curve cryptography (like secp256k1 used in Ethereum, Cosmos, and Avalanche’s C-Chain, and ed25519 used in NEAR) and specific cryptographic transformations such as hashing (Keccak-256 for Ethereum, SHA-256 for Cosmos, and various for Avalanche depending on the chain), truncating, and encoding (Bech32 for Cosmos and Avalanche, Base58 for NEAR).

Setting Up the LocalSigner

With your mnemonic and HD path ready, you can now configure and initialize the LocalSigner:

import { SolanaStaker } from '@chorus-one/solana'
import { LocalSigner } from '@chorus-one/signer-local'
import { KeyType } from '@chorus-one/signer'

const signer = new LocalSigner({
  mnemonic: 'your-mnemonic-phrase',
  accounts: [{ hdPath: 'your-hd-path' }],
  keyType: KeyType.ED25519,
  addressDerivationFn: SolanaStaker.getAddressDerivationFn()
})

await signer.init()

Further Reading

• BIP39 Mnemonic Code

• BIP32 HD Wallets

• LocalSigner API Reference