# ZoneRpcAuthentication.getSignPayload

Computes the sign payload for a Zone RPC authentication token.

When `userAddress` is provided, the payload is wrapped as `keccak256(0x04 || authHash || userAddress)` to match V2 keychain signing.

## Imports

:::code-group
```ts [Named]
import { ZoneRpcAuthentication } from 'ox/tempo'
```

```ts [Entrypoint]
import * as ZoneRpcAuthentication from 'ox/tempo/ZoneRpcAuthentication'
```
:::

## Examples

```ts twoslash
import { ZoneRpcAuthentication } from 'ox/tempo'

const authentication = ZoneRpcAuthentication.from({
  chainId: 4217000026,
  expiresAt: 1711235160,
  issuedAt: 1711234560,
  zoneId: 26
})

const payload =
  ZoneRpcAuthentication.getSignPayload(authentication)
```

## Definition

```ts
function getSignPayload(
  authentication: PartialBy<ZoneRpcAuthentication, 'version'>,
  options?: getSignPayload.Options,
): Hex.Hex
```

**Source:** [src/tempo/ZoneRpcAuthentication.ts](https://github.com/wevm/ox/blob/main/src/tempo/ZoneRpcAuthentication.ts#L428)

## Parameters

### authentication

* **Type:** `PartialBy<ZoneRpcAuthentication, 'version'>`

The Zone RPC authentication token.

### options

* **Type:** `getSignPayload.Options`
* **Optional**

Options.

#### options.userAddress

* **Type:** `Address.Address | undefined`
* **Optional**

Root account address for keychain access-key signing.

When provided, computes `keccak256(0x04 || authHash || userAddress)`
instead of the raw `authHash`.

## Return Type

The sign payload.

`Hex.Hex`