# encodeProtectedHeader

> **encodeProtectedHeader**(`fields`): [`Uint8Array`](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array)

Defined in: [packages/filecoin-encryption-envelope/src/cose/headers.ts:877](https://github.com/FilOzone/synapse-sdk/blob/bc8a4b093324ccef9b407251fcf4e91823c6f599/packages/filecoin-encryption-envelope/src/cose/headers.ts#L877)

Encode the protected header as a deterministically encoded CBOR map.

Deterministic encoding provides stable bytes and test vectors; authentication
still uses the exact protected bytes carried by each envelope.

## Parameters

| Parameter | Type |
| ------ | ------ |
| `fields` | [`ProtectedHeaderFields`](/reference/filoz/filecoin-encryption-envelope/namespaces/cose/interfaces/protectedheaderfields/) |

## Returns

[`Uint8Array`](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array)