# DecodedProtectedHeader

Defined in: [packages/filecoin-encryption-envelope/src/cose/headers.ts:113](https://github.com/FilOzone/synapse-sdk/blob/628d3a8812e8612a183a3abe3328169fb741260b/packages/filecoin-encryption-envelope/src/cose/headers.ts#L113)

A decoded protected header with its original encoded bytes.
Use `bytes` verbatim when building the Enc_structure.

## Extends

- `ProtectedHeaderFields`

## Properties

### alg

> **alg**: [`Alg`](/reference/filecoin-encryption-envelope/namespaces/cose/type-aliases/alg/)

Defined in: [packages/filecoin-encryption-envelope/src/cose/headers.ts:97](https://github.com/FilOzone/synapse-sdk/blob/628d3a8812e8612a183a3abe3328169fb741260b/packages/filecoin-encryption-envelope/src/cose/headers.ts#L97)

#### Inherited from

`ProtectedHeaderFields.alg`

***

### appMetadata?

> `optional` **appMetadata?**: [`AppMetadata`](/reference/filecoin-encryption-envelope/type-aliases/appmetadata/)

Defined in: [packages/filecoin-encryption-envelope/src/cose/headers.ts:106](https://github.com/FilOzone/synapse-sdk/blob/628d3a8812e8612a183a3abe3328169fb741260b/packages/filecoin-encryption-envelope/src/cose/headers.ts#L106)

Opaque authenticated metadata. This package carries but does not interpret it.

#### Inherited from

`ProtectedHeaderFields.appMetadata`

***

### bytes

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

Defined in: [packages/filecoin-encryption-envelope/src/cose/headers.ts:114](https://github.com/FilOzone/synapse-sdk/blob/628d3a8812e8612a183a3abe3328169fb741260b/packages/filecoin-encryption-envelope/src/cose/headers.ts#L114)

***

### chunkSize?

> `optional` **chunkSize?**: `number`

Defined in: [packages/filecoin-encryption-envelope/src/cose/headers.ts:102](https://github.com/FilOzone/synapse-sdk/blob/628d3a8812e8612a183a3abe3328169fb741260b/packages/filecoin-encryption-envelope/src/cose/headers.ts#L102)

Plaintext bytes per chunk. Required only for the chunked scheme.

#### Inherited from

`ProtectedHeaderFields.chunkSize`

***

### contentType?

> `optional` **contentType?**: `string` \| `number`

Defined in: [packages/filecoin-encryption-envelope/src/cose/headers.ts:100](https://github.com/FilOzone/synapse-sdk/blob/628d3a8812e8612a183a3abe3328169fb741260b/packages/filecoin-encryption-envelope/src/cose/headers.ts#L100)

#### Inherited from

`ProtectedHeaderFields.contentType`

***

### iv

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

Defined in: [packages/filecoin-encryption-envelope/src/cose/headers.ts:99](https://github.com/FilOzone/synapse-sdk/blob/628d3a8812e8612a183a3abe3328169fb741260b/packages/filecoin-encryption-envelope/src/cose/headers.ts#L99)

12-byte IV for AES-256-GCM or 7-byte base nonce for the chunked scheme.

#### Inherited from

`ProtectedHeaderFields.iv`

***

### plaintextLength?

> `optional` **plaintextLength?**: `number`

Defined in: [packages/filecoin-encryption-envelope/src/cose/headers.ts:104](https://github.com/FilOzone/synapse-sdk/blob/628d3a8812e8612a183a3abe3328169fb741260b/packages/filecoin-encryption-envelope/src/cose/headers.ts#L104)

Exact plaintext length, when known before encoding. Chunked scheme only.

#### Inherited from

`ProtectedHeaderFields.plaintextLength`