> ## Documentation Index
> Fetch the complete documentation index at: https://docs.qu.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# hashMessage

```ts theme={null}
function hashMessage(message): string
```

Computes the Quai Network equivalent of the [EIP-191](https://eips.ethereum.org/EIPS/eip-191) personal-sign message
digest to sign.

This prefixes the message with [**MessagePrefix**](/sdk/content/variables/MessagePrefix) and the decimal length of `message` and
computes the [**keccak256**](/sdk/content/functions/keccak256) digest.

If `message` is a string, it is converted to its UTF-8 bytes first. To compute the digest of a
[**DataHexString**](../types-aliases/DataHex), it must be converted to [**bytes**](../functions/getBytes).

## Parameters

| Parameter | Type                     | Description          |
| :-------- | :----------------------- | :------------------- |
| `message` | `string` \| `Uint8Array` | The message to hash. |

## Returns

`string`

The message digest.

## Example

```ts theme={null}
hashMessage('Hello World');

// Hashes the SIX (6) string characters, i.e.
// [ "0", "x", "4", "2", "4", "3" ]
hashMessage('0x4243');

// Hashes the TWO (2) bytes [ 0x42, 0x43 ]...
hashMessage(getBytes('0x4243'));

// ...which is equal to using data
hashMessage(new Uint8Array([0x42, 0x43]));
```

## Source

[hash/message.ts:39](https://github.com/dominant-strategies/quais.js/blob/c1c12d43f9d34c6baad2b0542bd6d0acd6fefcbf/src/hash/message.ts#L39)