# UnprotectedHeaderMap

> **UnprotectedHeaderMap** = [`Map`](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Map)\<[`CborValue`](/reference/filoz/filecoin-encryption-envelope/namespaces/cose/type-aliases/cborvalue/), [`CborValue`](/reference/filoz/filecoin-encryption-envelope/namespaces/cose/type-aliases/cborvalue/)\>

Defined in: [packages/filecoin-encryption-envelope/src/cose/headers.ts:119](https://github.com/FilOzone/synapse-sdk/blob/9ad84d812e1dd635b76420a7d9388555a04f31b6/packages/filecoin-encryption-envelope/src/cose/headers.ts#L119)

Content unprotected header map.

The encoder emits an empty map. Decoding accepts unknown non-critical
parameters, but rejects `crit`, Partial IV, and labels duplicated in the
protected header.