# Prf.tag

Creates a credential-bound PRF configuration from a UTF-8 tag.

Tags are public, stable identifiers. Use the same tag with the same credential to reproduce a PRF output.

## Imports

:::code-group
```ts [Named]
import { Prf } from 'ox'
```

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

## Examples

```ts twoslash
import { Prf, WebAuthn } from 'ox'

const credential = await WebAuthn.getCredential({
  credentialId: 'oZ48...',
  prf: Prf.tag('account.1')
})
```

## Definition

```ts
function tag(
  value: string,
): tag.ReturnType
```

**Source:** [src/core/Prf.ts](https://github.com/wevm/ox/blob/main/src/core/Prf.ts#L23)

## Parameters

### value

* **Type:** `string`

Tag to encode.

## Return Type

A credential-bound PRF configuration.

`tag.ReturnType`