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Integrate Embedded Wallets with the StarkNet Blockchain

While using the Embedded Wallets Web SDK (formerly Web3Auth) for a non-EVM chain like StarkNet, you can get the user's private key from the provider. Using this private key, you can use the corresponding libraries of the blockchain to make blockchain calls like getting a user's account, fetching balance, sign transaction, send transaction, read from and write to the smart contract, etc. We have highlighted a few methods here to get you started quickly.

note

The SDKs are now branded as MetaMask Embedded Wallet SDKs (formerly Web3Auth Plug and Play SDKs). Package names and APIs remain Web3Auth (for example, Web3Auth React SDK), and code snippets may reference web3auth identifiers.

Installation​

npm install --save web3 starknet elliptic bn.js @starkware-industries/starkware-crypto-utils

Initializing Provider​

Getting the chainConfig​

Get Account and Key​

Once a user logs in, the Embedded Wallets SDK returns a provider. Even though StarkNet is a layer 2 on Ethereum, it is not EVM compatible. Therefore, you cannot use the native EIP-1193 provider used for EVM blockchains; instead, use the private key directly to make calls.

Using the function, web3auth.provider.request({method: "private_key"}) from Web3Auth provider, the application can have access to the user's private key. However, we cannot use this key with StarkNet EC Curve specific signing functions, hence, we first derive the Stark Key using the getStarkKey() function.

On the underhood, it uses the starkwareCrypto.ec.keyFromPrivate() function, where we pass our Private key with the hex argument since it is hex encoded. Further, we get the public key from this using the starkwareCrypto.ec.keyFromPublic() function, and we take its X-coordinate using .pub.getX() which is our starkKey. We use this starkKey on StarkNet transactions.

For the deployAccount(), we use the file ArgentAccount.json which gives us the ABI of the compiled contract. We use that contract in Starknet's defaultProvider.deployContract() function to deploy the contract.

Get ArgentAccount.json from this gist.

import starkwareCrypto from '@starkware-industries/starkware-crypto-utils'
import { ec as elliptic } from 'elliptic'
/*
  Use code from the above Initializing Provider here
*/

// web3authProvider is web3auth.provider from above
const privateKey = await web3authProvider.request({ method: 'private_key' })
const keyPair = starkwareCrypto.ec.keyFromPrivate(privateKey, 'hex')
// get the account address from the public key
const account = starkwareCrypto.ec.keyFromPublic(keyPair.getPublic(true, 'hex'), 'hex')

// Use this key for the StarkNet transactions
const startKey = account.pub.getX().toString('hex')

Deploy Account​

import { AddTransactionResponse, defaultProvider } from 'starknet'
import starkwareCrypto from '@starkware-industries/starkware-crypto-utils'
import { ec as elliptic } from 'elliptic'
import CompiledAccountContractAbi from './ArgentAccount.json'
/*
  Use code from the above Initializing Provider here
*/

// web3authProvider is web3auth.provider from above
const privateKey = await web3authProvider.request({ method: 'private_key' })
const keyPair = starkwareCrypto.ec.keyFromPrivate(privateKey, 'hex')
// get the account address from the public key
const account = starkwareCrypto.ec.keyFromPublic(keyPair.getPublic(true, 'hex'), 'hex')

const contract = JSON.parse(JSON.stringify(CompiledAccountContractAbi))
const response = await defaultProvider.deployContract({ contract })
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