# HEADER_KID

> `const` **HEADER\_KID**: `4` = `4`

Defined in: [packages/filecoin-encryption-envelope/src/constants.ts:16](https://github.com/FilOzone/synapse-sdk/blob/4fe24ea1c76c9b1fa1489b7cdbb1cc279bd2576a/packages/filecoin-encryption-envelope/src/constants.ts#L16)

`kid`, RFC 9052 §3.1. Not used at the top level in this profile; kept for recipients.