# FrameSignature.assert

Asserts that a [`FrameSignature.FrameSignature`](/api/FrameSignature/types#framesignature) is structurally valid.

Checks metadata, signature scalars, and public key shape without verifying authorization.

## Imports

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

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

## Examples

### Basic Usage

Unsigned protocol entries are accepted by default.

```ts twoslash
import { FrameSignature } from 'ox'

FrameSignature.assert({
  payload: '0x',
  scheme: 'secp256k1'
})
```

### Requiring a Signature

Set `signed` to require a protocol signature.

```ts twoslash
import { FrameSignature, Hash, Secp256k1 } from 'ox'

const payload = Hash.keccak256('0xdeadbeef')
const privateKey = Secp256k1.randomPrivateKey()
const signature = Secp256k1.sign({ payload, privateKey })

const entry = FrameSignature.from({
  payload,
  scheme: 'secp256k1',
  signature
})

FrameSignature.assert(entry, { signed: true })
```

## Definition

```ts
function assert(
  entry: FrameSignature,
  options?: assert.Options,
): void
```

**Source:** [src/core/FrameSignature.ts](https://github.com/wevm/ox/blob/main/src/core/FrameSignature.ts#L131)

## Parameters

### entry

* **Type:** `FrameSignature`

The signature entry to assert.

#### entry.payload

* **Type:** `0x${string}`
* **Optional**

Explicit nonzero digest. Omit or use empty bytes for the transaction signing hash.

#### entry.publicKey

* **Type:** `{ prefix: number; x: 0x${string}; y: 0x${string}; }`
* **Optional**

Public key, if already known. Empty wire signatures do not retain it.

#### entry.scheme

* **Type:** `2 | "p256"`

P-256 verification scheme.

#### entry.signature

* **Type:** `{ r: 0x${string}; s: 0x${string}; yParity?: number; }`

P-256 signature.

#### entry.signer

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

Signer address. Omit to use the transaction sender.

### options

* **Type:** `assert.Options`
* **Optional**

Validation options.

#### options.signed

* **Type:** `boolean`
* **Optional**

Require a protocol signature. Does not perform cryptographic verification.

## Return Type

`void`