function getMessageHash(message: BrandedMessage): Uint8Array

hash = keccak256(
  "\x19Ethereum Signed Message:\n" +
  length(messageText) +
  messageText
)

const message = Siwe.create({
  domain: "example.com",
  address: Address("0x742d35Cc6634C0532925a3b844Bc9e7595f251e3"),
  uri: "https://example.com",
  chainId: 1,
});

const hash = Siwe.getMessageHash(message);
// Uint8Array(32) [...]
// Returns 32-byte hash ready for signing

// Browser wallet signing
const message = Siwe.create({ ... });
const text = Siwe.format(message);

// Wallet handles EIP-191 internally
const signature = await ethereum.request({
  method: 'personal_sign',
  params: [text, address],
});

// Get hash for signature verification
const hash = Siwe.getMessageHash(message);

// Recover public key from signature
const publicKey = Secp256k1.recoverPublicKey(signature, hash);

// Derive address and compare
const recoveredAddress = Address.fromPublicKey(publicKey.x, publicKey.y);
const valid = Address.equals(recoveredAddress, message.address);

import { Secp256k1 } from 'tevm';

const message = Siwe.create({ ... });
const hash = Siwe.getMessageHash(message);

// Sign with private key
const privateKey = Bytes32(); // Your private key
const signature = Secp256k1.sign(hash, privateKey);

const message = Siwe.create({ ... });
const hash = message.getMessageHash();
// Same as Siwe.getMessageHash(message)

0x19 <version byte>
"Ethereum Signed Message:\n" <message length>
<message>

// Wrong: Don't hash before wallet signing
const hash = Siwe.getMessageHash(message);
await wallet.signMessage(hash); // Wallet will hash again

// Correct: Send formatted text to wallet
const text = Siwe.format(message);
await wallet.signMessage(text); // Wallet applies EIP-191

// Correct: UTF-8 encoding
const messageBytes = new TextEncoder().encode(messageText);

// Wrong: Don't use hex or base64
const wrongBytes = hexToBytes(messageText); // No!

// Correct: ASCII decimal length
const length = messageBytes.length.toString(); // "145"

// Wrong: Don't use hex length
const wrongLength = messageBytes.length.toString(16); // "91" - No!