# pieceKey

> **pieceKey**(`node`, `salt`): [`Uint8Array`](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array)

Defined in: [derive.ts:298](https://github.com/FilOzone/synapse-sdk/blob/68e30a2a5457180e60a5579eb5ecff90b65894b3/packages/keysmith/src/derive.ts#L298)

The key for one piece. Never reused: FEE requires a fresh key per object.

## Parameters

| Parameter | Type |
| ------ | ------ |
| `node` | [`Uint8Array`](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array) |
| `salt` | `` `0x${string}` `` |

## Returns

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