Legacy Account Key

Import the @kaiachain/web3js-ext packages to add kaia features on web3

Define sender's address and private key

Set up the provider with the specified kairos testnet URL. A provider in web3js is a read-only abstraction to access the blockchain data.

Also, you can change the provider URL from kairos to quicknode

Define a web3 instance using the provider

Create a sender's wallet with the private key and provider

Define a message to be signed and recovered

Sign the message with sender's wallet

Recover the address from signed message using web3.eth.accounts.recover

Recover the address from signed message using web3.klay.recoverFromMessage

SignMsgWithLegacyExample.js

const { Web3 } = require("@kaiachain/web3js-ext");

const senderAddr = "0x24e8efd18d65bcb6b3ba15a4698c0b0d69d13ff7";

const senderPriv = "0x4a72b3d09c3d5e28e8652e0111f9c4ce252e8299aad95bb219a38eb0a3f4da49";

const provider = new Web3.providers.HttpProvider("https://public-en-kairos.node.kaia.io");

const web3 = new Web3(provider);

const senderAccount = web3.eth.accounts.privateKeyToAccount(senderPriv);

async function main() {

const msg = "hello";

const msghex = Web3.utils.utf8ToHex(msg);

const signResult = senderAccount.sign(msg);

console.log({ senderAddr, msg, msghex, sig: signResult.signature });

const { v, r, s } = signResult;

const addr1 = web3.eth.accounts.recover(msg, v, r, s);

console.log("recoveredAddr lib", addr1, addr1.toLowerCase() === senderAddr);

const sig = signResult.signature;

const addr2 = await web3.klay.recoverFromMessage(senderAddr, msghex, sig, "latest");

console.log("recoveredAddr rpc", addr2, addr2.toLowerCase() === senderAddr);

}

main().catch(console.error);

output

❯ js SignMsgWithLegacyExample.js

{

senderAddr: '0x24e8efd18d65bcb6b3ba15a4698c0b0d69d13ff7',

msg: 'hello',

msghex: '0x68656c6c6f',

sig: '0xcf6792ecd73ccc5efc1612f461bffa699e824a4ed64ec1073709c9d6b8c6daf608060326371544811e2015398f7e48ad839e1f3c551e8cb7c3c82f10d226bd671b'

}

recoveredAddr lib 0x24e8eFD18D65bCb6b3Ba15a4698c0b0d69d13fF7 true

recoveredAddr rpc 0x24e8efd18d65bcb6b3ba15a4698c0b0d69d13ff7 true